<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPolicies" xlink:href="saic-20200131.xsd#BusinessOverviewAndSummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:href="saic-20200131.xsd#BusinessOverviewAndSummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:href="saic-20200131.xsd#BusinessOverviewAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesReconciliationOfCashCashEquivalentsAndRestrictedCashDetails" xlink:href="saic-20200131.xsd#BusinessOverviewAndSummaryOfSignificantAccountingPoliciesReconciliationOfCashCashEquivalentsAndRestrictedCashDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesTables" xlink:href="saic-20200131.xsd#BusinessOverviewAndSummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/BusinessSegmentInformation" xlink:href="saic-20200131.xsd#BusinessSegmentInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/BusinessSegmentInformationDetails" xlink:href="saic-20200131.xsd#BusinessSegmentInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ChangesInAccumulatedOtherComprehensiveLossByComponent" xlink:href="saic-20200131.xsd#ChangesInAccumulatedOtherComprehensiveLossByComponent" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ChangesInAccumulatedOtherComprehensiveLossByComponentDetails" xlink:href="saic-20200131.xsd#ChangesInAccumulatedOtherComprehensiveLossByComponentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ChangesInAccumulatedOtherComprehensiveLossByComponentTables" xlink:href="saic-20200131.xsd#ChangesInAccumulatedOtherComprehensiveLossByComponentTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ConsolidatedBalanceSheets" xlink:href="saic-20200131.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="saic-20200131.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="saic-20200131.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:href="saic-20200131.xsd#ConsolidatedStatementsOfComprehensiveIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ConsolidatedStatementsOfEquity" xlink:href="saic-20200131.xsd#ConsolidatedStatementsOfEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ConsolidatedStatementsOfEquityParenthetical" xlink:href="saic-20200131.xsd#ConsolidatedStatementsOfEquityParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/ConsolidatedStatementsOfIncome" xlink:href="saic-20200131.xsd#ConsolidatedStatementsOfIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DebtObligations" xlink:href="saic-20200131.xsd#DebtObligations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DebtObligationsMaturitiesOfLongTermDebtDetails" xlink:href="saic-20200131.xsd#DebtObligationsMaturitiesOfLongTermDebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DebtObligationsNarrativeDetails" xlink:href="saic-20200131.xsd#DebtObligationsNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DebtObligationsScheduleOfLongTermDebtDetails" xlink:href="saic-20200131.xsd#DebtObligationsScheduleOfLongTermDebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DebtObligationsTables" xlink:href="saic-20200131.xsd#DebtObligationsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedges" xlink:href="saic-20200131.xsd#DerivativeInstrumentsDesignatedAsCashFlowHedges" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedgesNarrativeDetails" xlink:href="saic-20200131.xsd#DerivativeInstrumentsDesignatedAsCashFlowHedgesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedgesScheduleOfDerivativeInstrumentsDesignatedAsCashFlowHedgesDetails" xlink:href="saic-20200131.xsd#DerivativeInstrumentsDesignatedAsCashFlowHedgesScheduleOfDerivativeInstrumentsDesignatedAsCashFlowHedgesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedgesTables" xlink:href="saic-20200131.xsd#DerivativeInstrumentsDesignatedAsCashFlowHedgesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/DocumentAndEntityInformation" xlink:href="saic-20200131.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividends" xlink:href="saic-20200131.xsd#EarningsPerShareShareRepurchasesAndDividends" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividendsNarrativeDetails" xlink:href="saic-20200131.xsd#EarningsPerShareShareRepurchasesAndDividendsNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividendsScheduleOfWeightedAverageSharesOutstandingDetails" xlink:href="saic-20200131.xsd#EarningsPerShareShareRepurchasesAndDividendsScheduleOfWeightedAverageSharesOutstandingDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividendsTables" xlink:href="saic-20200131.xsd#EarningsPerShareShareRepurchasesAndDividendsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisition" xlink:href="saic-20200131.xsd#EngilityAcquisition" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisitionFairValueOfIntangibleAssetsAndRelatedWeightedAverageUsefulLivesDetails" xlink:href="saic-20200131.xsd#EngilityAcquisitionFairValueOfIntangibleAssetsAndRelatedWeightedAverageUsefulLivesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisitionFairValuesOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:href="saic-20200131.xsd#EngilityAcquisitionFairValuesOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisitionNarrativeDetails" xlink:href="saic-20200131.xsd#EngilityAcquisitionNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisitionProFormaDetails" xlink:href="saic-20200131.xsd#EngilityAcquisitionProFormaDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisitionScheduleOfAcquisitionAndIntegrationCostsDetails" xlink:href="saic-20200131.xsd#EngilityAcquisitionScheduleOfAcquisitionAndIntegrationCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisitionSummaryOfPreliminaryPurchaseConsiderationDetails" xlink:href="saic-20200131.xsd#EngilityAcquisitionSummaryOfPreliminaryPurchaseConsiderationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/EngilityAcquisitionTables" xlink:href="saic-20200131.xsd#EngilityAcquisitionTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/GoodwillAndIntangibleAssets" xlink:href="saic-20200131.xsd#GoodwillAndIntangibleAssets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/GoodwillAndIntangibleAssetsEstimatedAnnualAmortizationExpenseDetails" xlink:href="saic-20200131.xsd#GoodwillAndIntangibleAssetsEstimatedAnnualAmortizationExpenseDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/GoodwillAndIntangibleAssetsNarrativeDetails" xlink:href="saic-20200131.xsd#GoodwillAndIntangibleAssetsNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/GoodwillAndIntangibleAssetsScheduleOfIntangibleAssetsDetails" xlink:href="saic-20200131.xsd#GoodwillAndIntangibleAssetsScheduleOfIntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/GoodwillAndIntangibleAssetsTables" xlink:href="saic-20200131.xsd#GoodwillAndIntangibleAssetsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/IncomeTaxes" xlink:href="saic-20200131.xsd#IncomeTaxes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/IncomeTaxesNarrativeDetails" xlink:href="saic-20200131.xsd#IncomeTaxesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/IncomeTaxesProvisionForIncomeTaxesDetails" xlink:href="saic-20200131.xsd#IncomeTaxesProvisionForIncomeTaxesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/IncomeTaxesReconciliationOfProvisionForIncomeTaxesDetails" xlink:href="saic-20200131.xsd#IncomeTaxesReconciliationOfProvisionForIncomeTaxesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/IncomeTaxesScheduleOfChangesInUnrecognizedTaxBenefitsDetails" xlink:href="saic-20200131.xsd#IncomeTaxesScheduleOfChangesInUnrecognizedTaxBenefitsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/IncomeTaxesScheduleOfDeferredTaxAssetsLiabilitiesDetails" xlink:href="saic-20200131.xsd#IncomeTaxesScheduleOfDeferredTaxAssetsLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/IncomeTaxesTables" xlink:href="saic-20200131.xsd#IncomeTaxesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/Leases" xlink:href="saic-20200131.xsd#Leases" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LeasesAssetsAndLiabilitiesLeasesDetails" xlink:href="saic-20200131.xsd#LeasesAssetsAndLiabilitiesLeasesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LeasesLeaseCostDetails" xlink:href="saic-20200131.xsd#LeasesLeaseCostDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LeasesNarrativeAsc840Details" xlink:href="saic-20200131.xsd#LeasesNarrativeAsc840Details" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LeasesNarrativeAsc842Details" xlink:href="saic-20200131.xsd#LeasesNarrativeAsc842Details" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LeasesOperatingLeaseLiabilitiesPaymentsDueDetails" xlink:href="saic-20200131.xsd#LeasesOperatingLeaseLiabilitiesPaymentsDueDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LeasesOtherSupplementalLeaseInformationDetails" xlink:href="saic-20200131.xsd#LeasesOtherSupplementalLeaseInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LeasesTables" xlink:href="saic-20200131.xsd#LeasesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LegalProceedingsAndCommitmentsAndContingencies" xlink:href="saic-20200131.xsd#LegalProceedingsAndCommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/LegalProceedingsAndCommitmentsAndContingenciesDetails" xlink:href="saic-20200131.xsd#LegalProceedingsAndCommitmentsAndContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/PropertyPlantAndEquipment" xlink:href="saic-20200131.xsd#PropertyPlantAndEquipment" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/PropertyPlantAndEquipmentNarrativeDetails" xlink:href="saic-20200131.xsd#PropertyPlantAndEquipmentNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/PropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipmentDetails" xlink:href="saic-20200131.xsd#PropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipmentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/PropertyPlantAndEquipmentTables" xlink:href="saic-20200131.xsd#PropertyPlantAndEquipmentTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RestructuringAndImpairmentNarrativeDetails" xlink:href="saic-20200131.xsd#RestructuringAndImpairmentNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RestructuringAndImpairmentNotes" xlink:href="saic-20200131.xsd#RestructuringAndImpairmentNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RestructuringAndImpairmentScheduleOfRestructuringCostsDetails" xlink:href="saic-20200131.xsd#RestructuringAndImpairmentScheduleOfRestructuringCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RestructuringAndImpairmentTables" xlink:href="saic-20200131.xsd#RestructuringAndImpairmentTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlans" xlink:href="saic-20200131.xsd#RetirementPlans" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansAmountsRecognizedInBalanceSheetDetails" xlink:href="saic-20200131.xsd#RetirementPlansAmountsRecognizedInBalanceSheetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansAssumptionsUsedDetails" xlink:href="saic-20200131.xsd#RetirementPlansAssumptionsUsedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansEstimatedFutureBenefitPaymentDetails" xlink:href="saic-20200131.xsd#RetirementPlansEstimatedFutureBenefitPaymentDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansFairValueMeasurementPlanAssetsDetails" xlink:href="saic-20200131.xsd#RetirementPlansFairValueMeasurementPlanAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansNarrativeDetails" xlink:href="saic-20200131.xsd#RetirementPlansNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansNetPeriodicBenefitIncomeExpenseDetails" xlink:href="saic-20200131.xsd#RetirementPlansNetPeriodicBenefitIncomeExpenseDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansObligationsAndFundedStatusDetails" xlink:href="saic-20200131.xsd#RetirementPlansObligationsAndFundedStatusDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansScheduleOfGuaranteedDepositAccountsDetails" xlink:href="saic-20200131.xsd#RetirementPlansScheduleOfGuaranteedDepositAccountsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RetirementPlansTables" xlink:href="saic-20200131.xsd#RetirementPlansTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/Revenues" xlink:href="saic-20200131.xsd#Revenues" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RevenuesChangeInEstimatesOnContractsDetails" xlink:href="saic-20200131.xsd#RevenuesChangeInEstimatesOnContractsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RevenuesContractBalancesDetails" xlink:href="saic-20200131.xsd#RevenuesContractBalancesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RevenuesDeferredCostsDetails" xlink:href="saic-20200131.xsd#RevenuesDeferredCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RevenuesDisaggregationOfRevenuesDetails" xlink:href="saic-20200131.xsd#RevenuesDisaggregationOfRevenuesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RevenuesNarrativeDetails" xlink:href="saic-20200131.xsd#RevenuesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RevenuesPerformanceObligationDetails" xlink:href="saic-20200131.xsd#RevenuesPerformanceObligationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/RevenuesTables" xlink:href="saic-20200131.xsd#RevenuesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/SelectedQuarterlyFinancialDataUnaudited" xlink:href="saic-20200131.xsd#SelectedQuarterlyFinancialDataUnaudited" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/SelectedQuarterlyFinancialDataUnauditedDetails" xlink:href="saic-20200131.xsd#SelectedQuarterlyFinancialDataUnauditedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/SelectedQuarterlyFinancialDataUnauditedTables" xlink:href="saic-20200131.xsd#SelectedQuarterlyFinancialDataUnauditedTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensation" xlink:href="saic-20200131.xsd#StockBasedCompensation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationFairValueAndValuationAssumptionsOfStockOptionsDetails" xlink:href="saic-20200131.xsd#StockBasedCompensationFairValueAndValuationAssumptionsOfStockOptionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationNarrativeDetails" xlink:href="saic-20200131.xsd#StockBasedCompensationNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationScheduleOfPerformanceShareAwardActivityDetails" xlink:href="saic-20200131.xsd#StockBasedCompensationScheduleOfPerformanceShareAwardActivityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationScheduleOfSharedBasedCompensationCostRelatedToStockOptionsDetails" xlink:href="saic-20200131.xsd#StockBasedCompensationScheduleOfSharedBasedCompensationCostRelatedToStockOptionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationScheduleOfStockBasedCompensationExpenseAndRelatedTaxBenefitsDetails" xlink:href="saic-20200131.xsd#StockBasedCompensationScheduleOfStockBasedCompensationExpenseAndRelatedTaxBenefitsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationScheduleOfStockOptionActivityDetails" xlink:href="saic-20200131.xsd#StockBasedCompensationScheduleOfStockOptionActivityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationScheduleOfVestingStockAwardActivityDetails" xlink:href="saic-20200131.xsd#StockBasedCompensationScheduleOfVestingStockAwardActivityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/StockBasedCompensationTables" xlink:href="saic-20200131.xsd#StockBasedCompensationTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/SubsequentEventsDetails" xlink:href="saic-20200131.xsd#SubsequentEventsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.saic.com/role/SubsequentEventsNotes" xlink:href="saic-20200131.xsd#SubsequentEventsNotes" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="saic-20200131.xsd#saic_SignificantAccountingPoliciesLineItems" xlink:label="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:type="locator" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SignificantAccountingPoliciesTable" xlink:label="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_OwnershipAxis" xlink:label="loc_srt_OwnershipAxis_6C3C28CBB0076A3924AE084EB447A8B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:to="loc_srt_OwnershipAxis_6C3C28CBB0076A3924AE084EB447A8B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_OwnershipDomain" xlink:label="loc_srt_OwnershipDomain_265D36BE7E68727B0482084EB44824FA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_6C3C28CBB0076A3924AE084EB447A8B3" xlink:to="loc_srt_OwnershipDomain_265D36BE7E68727B0482084EB44824FA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_OwnershipDomain" xlink:label="loc_srt_OwnershipDomain_265D36BE7E68727B0482084EB44824FA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_6C3C28CBB0076A3924AE084EB447A8B3" xlink:to="loc_srt_OwnershipDomain_265D36BE7E68727B0482084EB44824FA" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ForfeitureSupportAssociatesJ.V.Member" xlink:label="loc_saic_ForfeitureSupportAssociatesJ.V.Member_39B21BD742D65FA0C3BE084EB448271A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_265D36BE7E68727B0482084EB44824FA" xlink:to="loc_saic_ForfeitureSupportAssociatesJ.V.Member_39B21BD742D65FA0C3BE084EB448271A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_C2E427B37BB493B41968084EB448AB29" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_C2E427B37BB493B41968084EB448AB29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_B3DA1199DD8C41F151C4084EB449CF39_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_C2E427B37BB493B41968084EB448AB29" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_B3DA1199DD8C41F151C4084EB449CF39_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_B3DA1199DD8C41F151C4084EB449CF39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_C2E427B37BB493B41968084EB448AB29" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_B3DA1199DD8C41F151C4084EB449CF39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_5FF79EECF3C143DA920D084EB4492395" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_B3DA1199DD8C41F151C4084EB449CF39" xlink:to="loc_us-gaap_CostOfSalesMember_5FF79EECF3C143DA920D084EB4492395" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_AC24BC515BF75BD197B5084EB44A9302" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_B3DA1199DD8C41F151C4084EB449CF39" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_AC24BC515BF75BD197B5084EB44A9302" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_AB8E3DEE5866E47B9ED5084EB44A7CC0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_AB8E3DEE5866E47B9ED5084EB44A7CC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_331905ABF6F9316EB6D4084EB44A8D90_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_AB8E3DEE5866E47B9ED5084EB44A7CC0" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_331905ABF6F9316EB6D4084EB44A8D90_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_331905ABF6F9316EB6D4084EB44A8D90" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_AB8E3DEE5866E47B9ED5084EB44A7CC0" xlink:to="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_331905ABF6F9316EB6D4084EB44A8D90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member" xlink:label="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_FBB49F51DE8427237867084EB44AE7B1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_331905ABF6F9316EB6D4084EB44A8D90" xlink:to="loc_us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_FBB49F51DE8427237867084EB44AE7B1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_E2C38BEFA53FD4758DB8084EB44C80E5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_E2C38BEFA53FD4758DB8084EB44C80E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_6DA4B70FE81E9E956A5D084EB44C5667_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_E2C38BEFA53FD4758DB8084EB44C80E5" xlink:to="loc_us-gaap_EquityComponentDomain_6DA4B70FE81E9E956A5D084EB44C5667_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_6DA4B70FE81E9E956A5D084EB44C5667" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_E2C38BEFA53FD4758DB8084EB44C80E5" xlink:to="loc_us-gaap_EquityComponentDomain_6DA4B70FE81E9E956A5D084EB44C5667" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_52B77AD61AC5ACCAD85D084EB44C3AA0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6DA4B70FE81E9E956A5D084EB44C5667" xlink:to="loc_us-gaap_RetainedEarningsMember_52B77AD61AC5ACCAD85D084EB44C3AA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_26D4F679A29D24D61F64084EB44D410A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6DA4B70FE81E9E956A5D084EB44C5667" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_26D4F679A29D24D61F64084EB44D410A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_53BBCF2A497A7B3D25E6084EB44D8F19" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_53BBCF2A497A7B3D25E6084EB44D8F19" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_5B25ABA295C1AFFE0447084EB44DDFB5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_53BBCF2A497A7B3D25E6084EB44D8F19" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_5B25ABA295C1AFFE0447084EB44DDFB5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_5B25ABA295C1AFFE0447084EB44DDFB5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_53BBCF2A497A7B3D25E6084EB44D8F19" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_5B25ABA295C1AFFE0447084EB44DDFB5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="loc_us-gaap_EmployeeSeveranceMember_7A8FD86A1B7C940B7209084EB44DF8F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_5B25ABA295C1AFFE0447084EB44DDFB5" xlink:to="loc_us-gaap_EmployeeSeveranceMember_7A8FD86A1B7C940B7209084EB44DF8F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_6F393F509E55549A55E8084EB44E6DE9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_6F393F509E55549A55E8084EB44E6DE9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E9AF27B2734001EA9EA0084EB44EE55D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6F393F509E55549A55E8084EB44E6DE9" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E9AF27B2734001EA9EA0084EB44EE55D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E9AF27B2734001EA9EA0084EB44EE55D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_6F393F509E55549A55E8084EB44E6DE9" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E9AF27B2734001EA9EA0084EB44EE55D" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ScitorHoldingsIncMember" xlink:label="loc_saic_ScitorHoldingsIncMember_F01CEE3C6C6EBB0D421F084EB44ECDBF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_E9AF27B2734001EA9EA0084EB44EE55D" xlink:to="loc_saic_ScitorHoldingsIncMember_F01CEE3C6C6EBB0D421F084EB44ECDBF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3C710EC65BD8A943CAAE084EB44F2368" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_SignificantAccountingPoliciesTable_6AA971619072D6C69EEA084EB4472F31" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3C710EC65BD8A943CAAE084EB44F2368" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_A7944E89B7BC3C9A6D26084EB44F1009_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3C710EC65BD8A943CAAE084EB44F2368" xlink:to="loc_us-gaap_TypeOfAdoptionMember_A7944E89B7BC3C9A6D26084EB44F1009_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_A7944E89B7BC3C9A6D26084EB44F1009" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_3C710EC65BD8A943CAAE084EB44F2368" xlink:to="loc_us-gaap_TypeOfAdoptionMember_A7944E89B7BC3C9A6D26084EB44F1009" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_AccountingStandardsUpdate201409RevenueRecognitionAdjustedCostToCostBasisMember" xlink:label="loc_saic_AccountingStandardsUpdate201409RevenueRecognitionAdjustedCostToCostBasisMember_C479C3AD9B817FD12306084EB44FD2F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_A7944E89B7BC3C9A6D26084EB44F1009" xlink:to="loc_saic_AccountingStandardsUpdate201409RevenueRecognitionAdjustedCostToCostBasisMember_C479C3AD9B817FD12306084EB44FD2F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingStandardsUpdate201609Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201609Member_9CCB03670294A2F820F2084EB4508038" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_A7944E89B7BC3C9A6D26084EB44F1009" xlink:to="loc_us-gaap_AccountingStandardsUpdate201609Member_9CCB03670294A2F820F2084EB4508038" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingStandardsUpdate201802Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201802Member_7EA71E525D3CA236EC29084EB450768B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_A7944E89B7BC3C9A6D26084EB44F1009" xlink:to="loc_us-gaap_AccountingStandardsUpdate201802Member_7EA71E525D3CA236EC29084EB450768B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_99A31B2FE5F4A504ECE4084EB450566D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_99A31B2FE5F4A504ECE4084EB450566D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_926B3E45E4811FFDB289084EB4516C34" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_926B3E45E4811FFDB289084EB4516C34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="loc_us-gaap_NumberOfOperatingSegments_A8AFE8D9C3E00C4B9B09084EB451508F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_NumberOfOperatingSegments_A8AFE8D9C3E00C4B9B09084EB451508F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="loc_us-gaap_NumberOfReportableSegments_FC697B9FCB6197DC5690084EB4518360" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_NumberOfReportableSegments_FC697B9FCB6197DC5690084EB4518360" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_2D641D07B5E9A2F59D5B084EB451C2D2" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_2D641D07B5E9A2F59D5B084EB451C2D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_0544A8EACAA9F3DCAC7D084EB452852F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_0544A8EACAA9F3DCAC7D084EB452852F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_60BE9544E371A37268C2084EB452E999" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_60BE9544E371A37268C2084EB452E999" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_OustandingChecks" xlink:label="loc_saic_OustandingChecks_53A7E0DAD8BFAD5C2BB3084EB4534313" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_saic_OustandingChecks_53A7E0DAD8BFAD5C2BB3084EB4534313" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ExpectedPeriodForRevenuesToBeBilledAndCollectedOnUncompletedContracts" xlink:label="loc_saic_ExpectedPeriodForRevenuesToBeBilledAndCollectedOnUncompletedContracts_5E04E09D901F4F652305084EB453FF95" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_saic_ExpectedPeriodForRevenuesToBeBilledAndCollectedOnUncompletedContracts_5E04E09D901F4F652305084EB453FF95" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GovernmentContractReceivableProgessPaymentsOffset" xlink:label="loc_us-gaap_GovernmentContractReceivableProgessPaymentsOffset_5EA78EEAC3ADC066EF2C084EB455FE90" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_GovernmentContractReceivableProgessPaymentsOffset_5EA78EEAC3ADC066EF2C084EB455FE90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InventoryFirmPurchaseCommitmentLoss" xlink:label="loc_us-gaap_InventoryFirmPurchaseCommitmentLoss_CDB1E6679629CF6CF50B084EB4551F62" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_InventoryFirmPurchaseCommitmentLoss_CDB1E6679629CF6CF50B084EB4551F62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetImpairment" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_D289684316B59629022D084EB455DD20" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_D289684316B59629022D084EB455DD20" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingCycle" xlink:label="loc_us-gaap_OperatingCycle_9996A117C94732CE7462084EB456C329" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_OperatingCycle_9996A117C94732CE7462084EB456C329" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_B5FD5E75BBE39D0BD185084EB4560A23" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_B5FD5E75BBE39D0BD185084EB4560A23" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_737DC97FD5C31131A100084EB456192C" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_737DC97FD5C31131A100084EB456192C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaap_OtherAssetsCurrent_DD153D34812F609E9060084EB45603A0" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_OtherAssetsCurrent_DD153D34812F609E9060084EB45603A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount_B389CC7C43C78D5B5AD7084EB45756EF" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount_B389CC7C43C78D5B5AD7084EB45756EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_4FF75E4BD23CCE21F46D084EB457B52B" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_4FF75E4BD23CCE21F46D084EB457B52B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_3339A87A6AFFFF3272DC084EB457D846" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_3339A87A6AFFFF3272DC084EB457D846" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaap_OperatingLeaseLiability_9A00B333A532AD9B6F30084EB4588DCE" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_OperatingLeaseLiability_9A00B333A532AD9B6F30084EB4588DCE" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TaxCutsAndJobsActReclassificationFromAOCIToRetainedEarningsTaxEffect" xlink:label="loc_saic_TaxCutsAndJobsActReclassificationFromAOCIToRetainedEarningsTaxEffect_9B6EC521FC05B76B637A084EB4584F59" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_saic_TaxCutsAndJobsActReclassificationFromAOCIToRetainedEarningsTaxEffect_9B6EC521FC05B76B637A084EB4584F59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MarketableSecuritiesNoncurrent" xlink:label="loc_us-gaap_MarketableSecuritiesNoncurrent_A8963A37925DC782378B084EB458216C" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_SignificantAccountingPoliciesLineItems_478751A069C3215A59EB084EB450C6FD" xlink:to="loc_us-gaap_MarketableSecuritiesNoncurrent_A8963A37925DC782378B084EB458216C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesReconciliationOfCashCashEquivalentsAndRestrictedCashDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/BusinessOverviewAndSummaryOfSignificantAccountingPoliciesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/BusinessSegmentInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/BusinessSegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_F8E49D09F459067517B7B0151B2E75D1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_45C56A93A963D39C2E45B0151B2ECE72" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_F8E49D09F459067517B7B0151B2E75D1" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_45C56A93A963D39C2E45B0151B2ECE72" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CD8BB5DA0019996C051DB0151B2E06C4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_45C56A93A963D39C2E45B0151B2ECE72" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CD8BB5DA0019996C051DB0151B2E06C4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5C5FF73933551B63F3AAB0151B2EE1BC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CD8BB5DA0019996C051DB0151B2E06C4" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5C5FF73933551B63F3AAB0151B2EE1BC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5C5FF73933551B63F3AAB0151B2EE1BC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_CD8BB5DA0019996C051DB0151B2E06C4" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5C5FF73933551B63F3AAB0151B2EE1BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SalesRevenueNetMember" xlink:label="loc_us-gaap_SalesRevenueNetMember_346D6DBCE0DB73B18E20B0151B2E9DCE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_5C5FF73933551B63F3AAB0151B2EE1BC" xlink:to="loc_us-gaap_SalesRevenueNetMember_346D6DBCE0DB73B18E20B0151B2E9DCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_677376664F018E302E95B0151B2EA92D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_45C56A93A963D39C2E45B0151B2ECE72" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_677376664F018E302E95B0151B2EA92D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_05025F3B66CB078256BDB0151B2E49F5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_677376664F018E302E95B0151B2EA92D" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_05025F3B66CB078256BDB0151B2E49F5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_05025F3B66CB078256BDB0151B2E49F5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_677376664F018E302E95B0151B2EA92D" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_05025F3B66CB078256BDB0151B2E49F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_1423D4F992C85C23B32EB0151B2E8377" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_05025F3B66CB078256BDB0151B2E49F5" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_1423D4F992C85C23B32EB0151B2E8377" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="loc_us-gaap_NumberOfOperatingSegments_D8250EF73706EC300564B0151B2E6268" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_F8E49D09F459067517B7B0151B2E75D1" xlink:to="loc_us-gaap_NumberOfOperatingSegments_D8250EF73706EC300564B0151B2E6268" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="loc_us-gaap_NumberOfReportableSegments_78CB97456D4E3907610CB0151B2E4E36" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_F8E49D09F459067517B7B0151B2E75D1" xlink:to="loc_us-gaap_NumberOfReportableSegments_78CB97456D4E3907610CB0151B2E4E36" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_FF9822C1233393D93EDAB0151B2EC36D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_F8E49D09F459067517B7B0151B2E75D1" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_FF9822C1233393D93EDAB0151B2EC36D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/ChangesInAccumulatedOtherComprehensiveLossByComponent" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/ChangesInAccumulatedOtherComprehensiveLossByComponentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_B55D8A38C39E91F0DFE512F5DEB88089" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1FA5561D822D7492802012F5DEB6BBCF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_B55D8A38C39E91F0DFE512F5DEB88089" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1FA5561D822D7492802012F5DEB6BBCF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_00924F16174C293986A7131197C9457C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1FA5561D822D7492802012F5DEB6BBCF" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_00924F16174C293986A7131197C9457C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_B4D244E970DEB0FAA0C0131197CCD174_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_00924F16174C293986A7131197C9457C" xlink:to="loc_us-gaap_TypeOfAdoptionMember_B4D244E970DEB0FAA0C0131197CCD174_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_B4D244E970DEB0FAA0C0131197CCD174" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_00924F16174C293986A7131197C9457C" xlink:to="loc_us-gaap_TypeOfAdoptionMember_B4D244E970DEB0FAA0C0131197CCD174" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingStandardsUpdate201802Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201802Member_572415FEE648ABFC1D4D1311D52D0A73" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_B4D244E970DEB0FAA0C0131197CCD174" xlink:to="loc_us-gaap_AccountingStandardsUpdate201802Member_572415FEE648ABFC1D4D1311D52D0A73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6D68C0B3EFA31852540312F5DEB7BEC0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1FA5561D822D7492802012F5DEB6BBCF" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6D68C0B3EFA31852540312F5DEB7BEC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_6B430EDCD3BBC317ED7C12F5DEB71673_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6D68C0B3EFA31852540312F5DEB7BEC0" xlink:to="loc_us-gaap_EquityComponentDomain_6B430EDCD3BBC317ED7C12F5DEB71673_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_6B430EDCD3BBC317ED7C12F5DEB71673" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6D68C0B3EFA31852540312F5DEB7BEC0" xlink:to="loc_us-gaap_EquityComponentDomain_6B430EDCD3BBC317ED7C12F5DEB71673" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember" xlink:label="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_3CD7EBC69211107794F712F5DEB79CBC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B430EDCD3BBC317ED7C12F5DEB71673" xlink:to="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_3CD7EBC69211107794F712F5DEB79CBC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_56540FEAA2D4BD87CDCB12F5DEB76C53" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B430EDCD3BBC317ED7C12F5DEB71673" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_56540FEAA2D4BD87CDCB12F5DEB76C53" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_F713C39DD7F05270BAFD12F5DEB8942D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B430EDCD3BBC317ED7C12F5DEB71673" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_F713C39DD7F05270BAFD12F5DEB8942D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_03F97648F4403D54B3B91305785DF194" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_B55D8A38C39E91F0DFE512F5DEB88089" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_03F97648F4403D54B3B91305785DF194" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_30873A1E8AF135716AA212F5DEBDC870" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_B55D8A38C39E91F0DFE512F5DEB88089" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_30873A1E8AF135716AA212F5DEBDC870" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_4C1FCB4A417D3E9DC5AB12F5DEBEBD77" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_B55D8A38C39E91F0DFE512F5DEB88089" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_4C1FCB4A417D3E9DC5AB12F5DEBEBD77" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_EC514244DC5B2EA96DBF12F5DEBE008E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_B55D8A38C39E91F0DFE512F5DEB88089" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_EC514244DC5B2EA96DBF12F5DEBE008E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_A777213D75906C40560C1301C04A2254" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_B55D8A38C39E91F0DFE512F5DEB88089" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_A777213D75906C40560C1301C04A2254" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/ChangesInAccumulatedOtherComprehensiveLossByComponentTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/ConsolidatedBalanceSheets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/ConsolidatedStatementsOfComprehensiveIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/ConsolidatedStatementsOfEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_307E3A3030E849A0A59C1346190D4342" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_4A043CF461B08F06EF1013461904419B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_307E3A3030E849A0A59C1346190D4342" xlink:to="loc_us-gaap_StatementTable_4A043CF461B08F06EF1013461904419B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_781BF68F3FD33356150713461907908A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_4A043CF461B08F06EF1013461904419B" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_781BF68F3FD33356150713461907908A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_781BF68F3FD33356150713461907908A" xlink:to="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_781BF68F3FD33356150713461907908A" xlink:to="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_BC0803CE8DD5045D5A9B13461908C945" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E" xlink:to="loc_us-gaap_CommonStockMember_BC0803CE8DD5045D5A9B13461908C945" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_08842918C18393B419881346190C9211" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_08842918C18393B419881346190C9211" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_DA5C3445403E5D62A6091346190CE445" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E" xlink:to="loc_us-gaap_RetainedEarningsMember_DA5C3445403E5D62A6091346190CE445" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_6B26440C60541D060F1F1346190CBCEF" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_6B26440C60541D060F1F1346190CBCEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_CF95943E79721F754AF21346190C1414" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_D8A0B3096AC15F8CAA2A13461907E28E" xlink:to="loc_us-gaap_NoncontrollingInterestMember_CF95943E79721F754AF21346190C1414" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_307E3A3030E849A0A59C1346190D4342" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_18FCA4AD001A05FF7F161346190E284A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_18FCA4AD001A05FF7F161346190E284A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_E7CF95087AE0B93691D01346190ED410" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_E7CF95087AE0B93691D01346190ED410" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_A8F109523BEC7191B7EF1346190EE10E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_A8F109523BEC7191B7EF1346190EE10E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaap_ProfitLoss_4C646E7055DF2B722A7C1346190F3888" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_ProfitLoss_4C646E7055DF2B722A7C1346190F3888" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_2F2524E606F36323915A1346190F7A28" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_NetIncomeLoss_2F2524E606F36323915A1346190F7A28" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_0F67E6AA5D5BF128E2F41346190FD256" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_0F67E6AA5D5BF128E2F41346190FD256" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_E20A24297912978808F71346190F70CA" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_E20A24297912978808F71346190F70CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_4CFF706FB49FB3E53016134619104870" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_4CFF706FB49FB3E53016134619104870" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect" xlink:label="loc_us-gaap_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect_AF524B63C7F6665AA1CB13461910817D" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect_AF524B63C7F6665AA1CB13461910817D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_BD5122E2DF2CEF2A1F1413461910DE7C" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_BD5122E2DF2CEF2A1F1413461910DE7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsCommonStockCash" xlink:label="loc_us-gaap_DividendsCommonStockCash_E851066EE3219E7D77B013461910E1E2" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_DividendsCommonStockCash_E851066EE3219E7D77B013461910E1E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_BA47BB5006D5851C133313461910E6F8" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_BA47BB5006D5851C133313461910E6F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_68912551409910567218134619111CEF" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_68912551409910567218134619111CEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_397E69D9296BE44720681346191171AB" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_397E69D9296BE44720681346191171AB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_CE96FD398D73A7AFB7A413461911AD7B" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_CE96FD398D73A7AFB7A413461911AD7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_F81BC16FEC9664CC4FD9134619116D9F" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_F81BC16FEC9664CC4FD9134619116D9F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_B5F61BB8CB514D5BEA9E13461912BA9B" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_B5F61BB8CB514D5BEA9E13461912BA9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_66D0644C6C8C92A70AD313461912C62C" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromBusinessCombination_66D0644C6C8C92A70AD313461912C62C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromMinorityShareholders" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_121E03F91B659FCC061B1346191210B3" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_6FB68BAB12FB11BFE3D61346190EE06C" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_121E03F91B659FCC061B1346191210B3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/ConsolidatedStatementsOfEquityParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/ConsolidatedStatementsOfIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/DebtObligations" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/DebtObligationsMaturitiesOfLongTermDebtDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/DebtObligationsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_BD1D34870C21CDC7A9B30DF95BDB7AFC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_BD1D34870C21CDC7A9B30DF95BDB7AFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_C848ECD8C93DFC73C02A0DF95BDB6A54_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_BD1D34870C21CDC7A9B30DF95BDB7AFC" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_C848ECD8C93DFC73C02A0DF95BDB6A54_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_C848ECD8C93DFC73C02A0DF95BDB6A54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_BD1D34870C21CDC7A9B30DF95BDB7AFC" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_C848ECD8C93DFC73C02A0DF95BDB6A54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_CADA761C18122BDD854E0DF95BDB8D51" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_C848ECD8C93DFC73C02A0DF95BDB6A54" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_CADA761C18122BDD854E0DF95BDB8D51" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_A8662C8ADD15D92337710DF95BDBA1CF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_C848ECD8C93DFC73C02A0DF95BDB6A54" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_A8662C8ADD15D92337710DF95BDBA1CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodThreeMember" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_84936E2A65B9B1DB7D3C0DF95BDB5D76" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_C848ECD8C93DFC73C02A0DF95BDB6A54" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_84936E2A65B9B1DB7D3C0DF95BDB5D76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_EF1C999597802C4D542A0DF95BDCFA89" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_EF1C999597802C4D542A0DF95BDCFA89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_87A51F2618CFF12D1EC40DF95BDC0F99_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_EF1C999597802C4D542A0DF95BDCFA89" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_87A51F2618CFF12D1EC40DF95BDC0F99_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_87A51F2618CFF12D1EC40DF95BDC0F99" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_EF1C999597802C4D542A0DF95BDCFA89" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_87A51F2618CFF12D1EC40DF95BDC0F99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_5D973EBFF01FEFAA23B20DF95BDC8629" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_87A51F2618CFF12D1EC40DF95BDC0F99" xlink:to="loc_us-gaap_SubsequentEventMember_5D973EBFF01FEFAA23B20DF95BDC8629" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtCovenantPeriodAxis" xlink:label="loc_saic_DebtCovenantPeriodAxis_ADC8CB761F1996C5F9270DF95BDCCC57" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_saic_DebtCovenantPeriodAxis_ADC8CB761F1996C5F9270DF95BDCCC57" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtCovenantPeriodDomain" xlink:label="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_saic_DebtCovenantPeriodAxis_ADC8CB761F1996C5F9270DF95BDCCC57" xlink:to="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900_default" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtCovenantPeriodDomain" xlink:label="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_saic_DebtCovenantPeriodAxis_ADC8CB761F1996C5F9270DF95BDCCC57" xlink:to="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_FirstTermMember" xlink:label="loc_saic_FirstTermMember_E8858891E5C48C71E1ED0DF95BDD54D8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900" xlink:to="loc_saic_FirstTermMember_E8858891E5C48C71E1ED0DF95BDD54D8" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SecondTermMember" xlink:label="loc_saic_SecondTermMember_FFE3F717F13C9AAEF26E0DF95BDD5C38" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900" xlink:to="loc_saic_SecondTermMember_FFE3F717F13C9AAEF26E0DF95BDD5C38" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ThirdTermMember" xlink:label="loc_saic_ThirdTermMember_FD3F146C91D6A2B7F3370DF95BDD8058" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900" xlink:to="loc_saic_ThirdTermMember_FD3F146C91D6A2B7F3370DF95BDD8058" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_FourthTermMember" xlink:label="loc_saic_FourthTermMember_82275EA83BAA0484D75E0DF95BDE3543" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_DebtCovenantPeriodDomain_D09EB6CC1AB33F7D20C50DF95BDD6900" xlink:to="loc_saic_FourthTermMember_82275EA83BAA0484D75E0DF95BDE3543" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_64D625F0C357B249A75C0DF95BDE3F94" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_us-gaap_CreditFacilityAxis_64D625F0C357B249A75C0DF95BDE3F94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_64D625F0C357B249A75C0DF95BDE3F94" xlink:to="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_64D625F0C357B249A75C0DF95BDE3F94" xlink:to="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SecuredDebtMember" xlink:label="loc_us-gaap_SecuredDebtMember_7DA262E0AF644419C2560DF95BDE1F98" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525" xlink:to="loc_us-gaap_SecuredDebtMember_7DA262E0AF644419C2560DF95BDE1F98" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ThirdAmendedCreditAgreementMember" xlink:label="loc_saic_ThirdAmendedCreditAgreementMember_43FD04EB902EB2E9BC9D0DF95BDF7EC2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525" xlink:to="loc_saic_ThirdAmendedCreditAgreementMember_43FD04EB902EB2E9BC9D0DF95BDF7EC2" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SecondAmendedAndRestatedCreditAgreementMember" xlink:label="loc_saic_SecondAmendedAndRestatedCreditAgreementMember_E6D4A11B0B5B21D817B10DF95BDF6206" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525" xlink:to="loc_saic_SecondAmendedAndRestatedCreditAgreementMember_E6D4A11B0B5B21D817B10DF95BDF6206" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_27B818CA311A2A51902E0DF95BDF88F0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_D30CFDBE1E75129299280DF95BDE6525" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_27B818CA311A2A51902E0DF95BDF88F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_E66DC433F74655F7D8210DF95BDF6E7D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_us-gaap_DebtInstrumentAxis_E66DC433F74655F7D8210DF95BDF6E7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_E66DC433F74655F7D8210DF95BDF6E7D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_E66DC433F74655F7D8210DF95BDF6E7D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_February2019CreditFacilityMember" xlink:label="loc_saic_February2019CreditFacilityMember_5EBC7C0DEFEFB1A402270DF95BE03843" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_February2019CreditFacilityMember_5EBC7C0DEFEFB1A402270DF95BE03843" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_February2019CreditFacilityTermLoanAMember" xlink:label="loc_saic_February2019CreditFacilityTermLoanAMember_5504168B3805E12232470DF95BE023EC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_February2019CreditFacilityTermLoanAMember_5504168B3805E12232470DF95BE023EC" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_February2019CreditFacilityTermLoanBMember" xlink:label="loc_saic_February2019CreditFacilityTermLoanBMember_65E9135DB60C851AABC00DF95BE52476" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_February2019CreditFacilityTermLoanBMember_65E9135DB60C851AABC00DF95BE52476" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_CreditFacilitydueAugust2021Member" xlink:label="loc_saic_CreditFacilitydueAugust2021Member_AA6B7934A39CEFBA40600DF95BE54764" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_CreditFacilitydueAugust2021Member_AA6B7934A39CEFBA40600DF95BE54764" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TermLoanAFacilityDueAugustTwoThousandTwentyOneMember" xlink:label="loc_saic_TermLoanAFacilityDueAugustTwoThousandTwentyOneMember_448E49C593953C6CE0530DF95BE68B7A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_TermLoanAFacilityDueAugustTwoThousandTwentyOneMember_448E49C593953C6CE0530DF95BE68B7A" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TermLoanBFacilityDueMayTwoThousandTwentyTwoMember" xlink:label="loc_saic_TermLoanBFacilityDueMayTwoThousandTwentyTwoMember_97950CB78E290BEAD5CA0DF95BE6566B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_TermLoanBFacilityDueMayTwoThousandTwentyTwoMember_97950CB78E290BEAD5CA0DF95BE6566B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_075080DC8C953423812C0DF95BE6CBE6" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_075080DC8C953423812C0DF95BE6CBE6" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TermLoanBFacilityDueOctoberTwoThousandTwentyFiveMember" xlink:label="loc_saic_TermLoanBFacilityDueOctoberTwoThousandTwentyFiveMember_7463B66C193F98CCF8A20DF95BE658B5" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_TermLoanBFacilityDueOctoberTwoThousandTwentyFiveMember_7463B66C193F98CCF8A20DF95BE658B5" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TermLoanAFacilityDueOctoberTwoThousandTwentyThreeMember" xlink:label="loc_saic_TermLoanAFacilityDueOctoberTwoThousandTwentyThreeMember_FC703EFEFF787030D9740DF95BE62575" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_2AC70E54D2318E58DC3B0DF95BDFB51E" xlink:to="loc_saic_TermLoanAFacilityDueOctoberTwoThousandTwentyThreeMember_FC703EFEFF787030D9740DF95BE62575" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_90E7735C219F1DD1F08B0DF95BE75E59" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_90E7735C219F1DD1F08B0DF95BE75E59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7918D8BB60943234291D0DF95BE78C63_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_90E7735C219F1DD1F08B0DF95BE75E59" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7918D8BB60943234291D0DF95BE78C63_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7918D8BB60943234291D0DF95BE78C63" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_90E7735C219F1DD1F08B0DF95BE75E59" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7918D8BB60943234291D0DF95BE78C63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="loc_us-gaap_LineOfCreditMember_6B472F9D9E9EDB73620D0DF95BE7C4BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_7918D8BB60943234291D0DF95BE78C63" xlink:to="loc_us-gaap_LineOfCreditMember_6B472F9D9E9EDB73620D0DF95BE7C4BE" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ThirdAmendedCreditAgreementMember" xlink:label="loc_saic_ThirdAmendedCreditAgreementMember_3D87F55F56CFFF5A09F60DF95BE728E2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_7918D8BB60943234291D0DF95BE78C63" xlink:to="loc_saic_ThirdAmendedCreditAgreementMember_3D87F55F56CFFF5A09F60DF95BE728E2" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SecondAmendedAndRestatedCreditAgreementMember" xlink:label="loc_saic_SecondAmendedAndRestatedCreditAgreementMember_9A7D04411BC18224A5DB0DF95BE75F60" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_7918D8BB60943234291D0DF95BE78C63" xlink:to="loc_saic_SecondAmendedAndRestatedCreditAgreementMember_9A7D04411BC18224A5DB0DF95BE75F60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_12B17B73302F54DCC0A80DF95BE8071E" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_srt_RangeAxis_12B17B73302F54DCC0A80DF95BE8071E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_5B3FF9B180F228AC5BAA0DF95BE89EF7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_12B17B73302F54DCC0A80DF95BE8071E" xlink:to="loc_srt_RangeMember_5B3FF9B180F228AC5BAA0DF95BE89EF7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_5B3FF9B180F228AC5BAA0DF95BE89EF7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_12B17B73302F54DCC0A80DF95BE8071E" xlink:to="loc_srt_RangeMember_5B3FF9B180F228AC5BAA0DF95BE89EF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_9F5D2D6123963B09DFC70DF95BE811C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5B3FF9B180F228AC5BAA0DF95BE89EF7" xlink:to="loc_srt_MinimumMember_9F5D2D6123963B09DFC70DF95BE811C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_378288ACFDC30F4ADFDD0DF95BE93382" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_5B3FF9B180F228AC5BAA0DF95BE89EF7" xlink:to="loc_srt_MaximumMember_378288ACFDC30F4ADFDD0DF95BE93382" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_A4E755030C28F61D79F60DF95BE902E2" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3C6154B26507E26927D40DF95BDA8B82" xlink:to="loc_us-gaap_VariableRateAxis_A4E755030C28F61D79F60DF95BE902E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_FBAF5AD208F22BEDAEB60DF95BE9DFC1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_A4E755030C28F61D79F60DF95BE902E2" xlink:to="loc_us-gaap_VariableRateDomain_FBAF5AD208F22BEDAEB60DF95BE9DFC1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_FBAF5AD208F22BEDAEB60DF95BE9DFC1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_A4E755030C28F61D79F60DF95BE902E2" xlink:to="loc_us-gaap_VariableRateDomain_FBAF5AD208F22BEDAEB60DF95BE9DFC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EurodollarMember" xlink:label="loc_us-gaap_EurodollarMember_DA9B0837CFCD4FFC695A0DF95BE9DE59" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_FBAF5AD208F22BEDAEB60DF95BE9DFC1" xlink:to="loc_us-gaap_EurodollarMember_DA9B0837CFCD4FFC695A0DF95BE9DE59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BaseRateMember" xlink:label="loc_us-gaap_BaseRateMember_2AFB0543B10E2E20AAC70DF95BEAD38F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_FBAF5AD208F22BEDAEB60DF95BE9DFC1" xlink:to="loc_us-gaap_BaseRateMember_2AFB0543B10E2E20AAC70DF95BEAD38F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_72685D1CAAD0ECA704DD0DF95BEA101E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_FBAF5AD208F22BEDAEB60DF95BE9DFC1" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_72685D1CAAD0ECA704DD0DF95BEA101E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_97BB5EB8ED5E75011E050DF95BEA44D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_97BB5EB8ED5E75011E050DF95BEA44D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_DFE92B6722B21EAE726A0DF95BEA1AEF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_DFE92B6722B21EAE726A0DF95BEA1AEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLinesOfCredit_CD3342660BDD0F9BC20F0DF9A72EB9A6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_ProceedsFromLinesOfCredit_CD3342660BDD0F9BC20F0DF9A72EB9A6" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtInstrumentReductionToInterestRateMargin" xlink:label="loc_saic_DebtInstrumentReductionToInterestRateMargin_06F08C1A8C330C393AB20DF95BEBC18C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_saic_DebtInstrumentReductionToInterestRateMargin_06F08C1A8C330C393AB20DF95BEBC18C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_E355D8639328E7ABF8E50DF95BEBD11D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_E355D8639328E7ABF8E50DF95BEBD11D" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtInstrumentFloorRate" xlink:label="loc_saic_DebtInstrumentFloorRate_38E22F0E3B74DA9684BE0DF95BEBE4DC" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_saic_DebtInstrumentFloorRate_38E22F0E3B74DA9684BE0DF95BEBE4DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_B443996C355B87D99FE10DF95BEB87EF" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_B443996C355B87D99FE10DF95BEB87EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_59754D5B294D4C5C82F80DF95BEB9BFE" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_59754D5B294D4C5C82F80DF95BEB9BFE" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_LongTermDebtGrossMergerTerminationFeature" xlink:label="loc_saic_LongTermDebtGrossMergerTerminationFeature_0738AB951FEFEA67A3D80DF95BEC9C8F" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_saic_LongTermDebtGrossMergerTerminationFeature_0738AB951FEFEA67A3D80DF95BEC9C8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_2800D9087D23E65BC0440DF95BEC2985" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_InterestExpense_2800D9087D23E65BC0440DF95BEC2985" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_B0C71DE6806B58DF35B10DF95BEC18E5" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_B0C71DE6806B58DF35B10DF95BEC18E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_8AF4CC2E281A7630A9F80DF95BECDBBC" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_8AF4CC2E281A7630A9F80DF95BECDBBC" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtInstrumentAmortizationRate" xlink:label="loc_saic_DebtInstrumentAmortizationRate_6C5D747A8B574B5701B30DF95BEC97A3" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_saic_DebtInstrumentAmortizationRate_6C5D747A8B574B5701B30DF95BEC97A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_A43B0AD34C9BD184743E0DF95BECFB74" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_A43B0AD34C9BD184743E0DF95BECFB74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_CADF329AAEA3EC4E8F630DF95BEDF64C" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_CADF329AAEA3EC4E8F630DF95BEDF64C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RatioOfIndebtednessToEarningsBeforeInterestTaxesDepreciationAndAmortization" xlink:label="loc_saic_RatioOfIndebtednessToEarningsBeforeInterestTaxesDepreciationAndAmortization_3158AC7D9A4E7E26E7710DF95BEDBFB9" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_F0B24A6DC3E47119AAB00DF95BEAC87E" xlink:to="loc_saic_RatioOfIndebtednessToEarningsBeforeInterestTaxesDepreciationAndAmortization_3158AC7D9A4E7E26E7710DF95BEDBFB9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/DebtObligationsScheduleOfLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_C13C77246AD85EE88FB0B0151C57FCDE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_DebtInstrumentTable_C13C77246AD85EE88FB0B0151C57FCDE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_8A2B31A12A1B7AACF302B0151C57712D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_C13C77246AD85EE88FB0B0151C57FCDE" xlink:to="loc_us-gaap_DebtInstrumentAxis_8A2B31A12A1B7AACF302B0151C57712D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_8A2B31A12A1B7AACF302B0151C57712D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_8A2B31A12A1B7AACF302B0151C57712D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_February2019CreditFacilityTermLoanAMember" xlink:label="loc_saic_February2019CreditFacilityTermLoanAMember_DC5B9914BB4DD392F1CAB0151C5711EB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B" xlink:to="loc_saic_February2019CreditFacilityTermLoanAMember_DC5B9914BB4DD392F1CAB0151C5711EB" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TermLoanAFacilityDueAugustTwoThousandTwentyOneMember" xlink:label="loc_saic_TermLoanAFacilityDueAugustTwoThousandTwentyOneMember_749F7E41F86F3D4A8971B0151C57DD9C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B" xlink:to="loc_saic_TermLoanAFacilityDueAugustTwoThousandTwentyOneMember_749F7E41F86F3D4A8971B0151C57DD9C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_February2019CreditFacilityTermLoanBMember" xlink:label="loc_saic_February2019CreditFacilityTermLoanBMember_65C5F5AB78995F67320BB0151C575F04" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B" xlink:to="loc_saic_February2019CreditFacilityTermLoanBMember_65C5F5AB78995F67320BB0151C575F04" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TermLoanBFacilityDueMayTwoThousandTwentyTwoMember" xlink:label="loc_saic_TermLoanBFacilityDueMayTwoThousandTwentyTwoMember_B508DEF10CA0601F044DB0151C5732D8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0719A71A4EA5D6D68926B0151C57556B" xlink:to="loc_saic_TermLoanBFacilityDueMayTwoThousandTwentyTwoMember_B508DEF10CA0601F044DB0151C5732D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_FAB7FE496BD68A057445B0151C57694D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_FAB7FE496BD68A057445B0151C57694D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_A7BDDACEDEC6DF2D20B5B0151C57E563" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_A7BDDACEDEC6DF2D20B5B0151C57E563" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_74DC7DB0C61D469BB554B0151C57F2B8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_74DC7DB0C61D469BB554B0151C57F2B8" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtInstrumentCurrentCarryingAmount" xlink:label="loc_saic_DebtInstrumentCurrentCarryingAmount_4836A32D34DD54FA3AC4B0151C570D7E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_saic_DebtInstrumentCurrentCarryingAmount_4836A32D34DD54FA3AC4B0151C570D7E" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DebtInstrumentNonCurrentCarryingAmount" xlink:label="loc_saic_DebtInstrumentNonCurrentCarryingAmount_AE54751D8D419A01A3BEB0151C572D38" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_saic_DebtInstrumentNonCurrentCarryingAmount_AE54751D8D419A01A3BEB0151C572D38" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_692B7C399CCB8F841F76B0151C572FB4" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_692B7C399CCB8F841F76B0151C572FB4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredFinanceCostsCurrentNet" xlink:label="loc_us-gaap_DeferredFinanceCostsCurrentNet_7CCA0F14D8825305C414B0151C57A30B" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_DeferredFinanceCostsCurrentNet_7CCA0F14D8825305C414B0151C57A30B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_FA9E763CF35C3B66A767B0151C5786DE" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_FA9E763CF35C3B66A767B0151C5786DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_9E8DACE768F22BDBB3B9B0151C575CB9" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_LongTermDebt_9E8DACE768F22BDBB3B9B0151C575CB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaap_LongTermDebtCurrent_1ACBD7C682B2425E3E77B0151C578E33" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_LongTermDebtCurrent_1ACBD7C682B2425E3E77B0151C578E33" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_C6645F03192CEA7B8C20B0151C578FD7" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_6DDF7B942E9D23AEB388B0151C5716AD" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_C6645F03192CEA7B8C20B0151C578FD7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/DebtObligationsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedges" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedgesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_A4F2ECFE0936BAAB62F512F5DED78E1F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_7F432FDCA4648C2A25D012F5DED44335" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_A4F2ECFE0936BAAB62F512F5DED78E1F" xlink:to="loc_us-gaap_DerivativeTable_7F432FDCA4648C2A25D012F5DED44335" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_F000D6D55C5F3AB3914A12F5DED59BBA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_7F432FDCA4648C2A25D012F5DED44335" xlink:to="loc_us-gaap_DebtInstrumentAxis_F000D6D55C5F3AB3914A12F5DED59BBA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_32E2D036802561A2C95912F5DED52E53_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_F000D6D55C5F3AB3914A12F5DED59BBA" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_32E2D036802561A2C95912F5DED52E53_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_32E2D036802561A2C95912F5DED52E53" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_F000D6D55C5F3AB3914A12F5DED59BBA" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_32E2D036802561A2C95912F5DED52E53" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_InterestRateSwapNumberFourMember" xlink:label="loc_saic_InterestRateSwapNumberFourMember_281ADB552B74F593C2F612F5DED52302" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_32E2D036802561A2C95912F5DED52E53" xlink:to="loc_saic_InterestRateSwapNumberFourMember_281ADB552B74F593C2F612F5DED52302" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_8BE046BBA02953C32FA512F5DED57CA6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_7F432FDCA4648C2A25D012F5DED44335" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_8BE046BBA02953C32FA512F5DED57CA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_00321B0C5199B32F256512F5DED68B43_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_8BE046BBA02953C32FA512F5DED57CA6" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_00321B0C5199B32F256512F5DED68B43_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_00321B0C5199B32F256512F5DED68B43" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_8BE046BBA02953C32FA512F5DED57CA6" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_00321B0C5199B32F256512F5DED68B43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_B3B1BA9FAB4F23F9C01012F5DED6E062" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_00321B0C5199B32F256512F5DED68B43" xlink:to="loc_us-gaap_InterestRateSwapMember_B3B1BA9FAB4F23F9C01012F5DED6E062" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeCashReceivedOnHedge" xlink:label="loc_us-gaap_DerivativeCashReceivedOnHedge_3F48D2DDD78A9248D79D12F5DED7EC10" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A4F2ECFE0936BAAB62F512F5DED78E1F" xlink:to="loc_us-gaap_DerivativeCashReceivedOnHedge_3F48D2DDD78A9248D79D12F5DED7EC10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet" xlink:label="loc_us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_938BE2B5AE61FCB5D6CA12F5DED7F658" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A4F2ECFE0936BAAB62F512F5DED78E1F" xlink:to="loc_us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_938BE2B5AE61FCB5D6CA12F5DED7F658" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet" xlink:label="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_0FF458DE6541F33EA65912F5DED798BE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A4F2ECFE0936BAAB62F512F5DED78E1F" xlink:to="loc_us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet_0FF458DE6541F33EA65912F5DED798BE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedgesScheduleOfDerivativeInstrumentsDesignatedAsCashFlowHedgesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_A77097E1BBBD8AC2608412F5DEE5B706" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_8B27CB49C497523B8B5312F5DEE2E364" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_A77097E1BBBD8AC2608412F5DEE5B706" xlink:to="loc_us-gaap_DerivativeTable_8B27CB49C497523B8B5312F5DEE2E364" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_384A600160DA666F17E012F5DEE3F1CC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_8B27CB49C497523B8B5312F5DEE2E364" xlink:to="loc_us-gaap_DebtInstrumentAxis_384A600160DA666F17E012F5DEE3F1CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_A7F8451094D70F000FA312F5DEE337F2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_384A600160DA666F17E012F5DEE3F1CC" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_A7F8451094D70F000FA312F5DEE337F2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_A7F8451094D70F000FA312F5DEE337F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_384A600160DA666F17E012F5DEE3F1CC" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_A7F8451094D70F000FA312F5DEE337F2" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_InterestRateSwapNumberOneMember" xlink:label="loc_saic_InterestRateSwapNumberOneMember_2B0114AD5CDECF8B2C7A12F5DEE3C45F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_A7F8451094D70F000FA312F5DEE337F2" xlink:to="loc_saic_InterestRateSwapNumberOneMember_2B0114AD5CDECF8B2C7A12F5DEE3C45F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_InterestRateSwapNumberTwoMember" xlink:label="loc_saic_InterestRateSwapNumberTwoMember_CC36293F18F795920E8C12F5DEE42A20" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_A7F8451094D70F000FA312F5DEE337F2" xlink:to="loc_saic_InterestRateSwapNumberTwoMember_CC36293F18F795920E8C12F5DEE42A20" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_InterestRateSwapNumberThreeMember" xlink:label="loc_saic_InterestRateSwapNumberThreeMember_A2FA3B4CCB83994677EE12F5DEE41F3A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_A7F8451094D70F000FA312F5DEE337F2" xlink:to="loc_saic_InterestRateSwapNumberThreeMember_A2FA3B4CCB83994677EE12F5DEE41F3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_C146472C973EC938A1B212F5DEE47085" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_8B27CB49C497523B8B5312F5DEE2E364" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_C146472C973EC938A1B212F5DEE47085" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_037CF092F7DA7D54BBFB12F5DEE47677_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_C146472C973EC938A1B212F5DEE47085" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_037CF092F7DA7D54BBFB12F5DEE47677_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_037CF092F7DA7D54BBFB12F5DEE47677" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_C146472C973EC938A1B212F5DEE47085" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_037CF092F7DA7D54BBFB12F5DEE47677" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="loc_us-gaap_InterestRateSwapMember_6339166E4625C2BFF8C512F5DEE462E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_037CF092F7DA7D54BBFB12F5DEE47677" xlink:to="loc_us-gaap_InterestRateSwapMember_6339166E4625C2BFF8C512F5DEE462E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeNotionalAmount" xlink:label="loc_us-gaap_DerivativeNotionalAmount_C6CEED53B04C0C0462BF12F5DEE59EA2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A77097E1BBBD8AC2608412F5DEE5B706" xlink:to="loc_us-gaap_DerivativeNotionalAmount_C6CEED53B04C0C0462BF12F5DEE59EA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeFixedInterestRate" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_5DF039442FA120A5C43312F5DEE50C47" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A77097E1BBBD8AC2608412F5DEE5B706" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_5DF039442FA120A5C43312F5DEE50C47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" xlink:label="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_3F23FBEA755CC50FCF1812F5DEE50EB9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A77097E1BBBD8AC2608412F5DEE5B706" xlink:to="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_3F23FBEA755CC50FCF1812F5DEE50EB9" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DerivativeContractSettlementAndTermination" xlink:label="loc_saic_DerivativeContractSettlementAndTermination_D44F81A1497CEAC9AB2E12F5DEE5AB66" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A77097E1BBBD8AC2608412F5DEE5B706" xlink:to="loc_saic_DerivativeContractSettlementAndTermination_D44F81A1497CEAC9AB2E12F5DEE5AB66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet" xlink:label="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_8FC61A4765C05DBFD54412F5DEE60950" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_A77097E1BBBD8AC2608412F5DEE5B706" xlink:to="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_8FC61A4765C05DBFD54412F5DEE60950" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/DerivativeInstrumentsDesignatedAsCashFlowHedgesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/DocumentAndEntityInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividends" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividendsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="saic-20200131.xsd#saic_ComputationOfEarningsPerShareLineItems" xlink:label="loc_saic_ComputationOfEarningsPerShareLineItems_7E538F0DEEBC1C33183A07C70BB18EA2" xlink:type="locator" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EarningsPerShareTable" xlink:label="loc_saic_EarningsPerShareTable_782A68842C5935E63F4307C70BAD3971" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_7E538F0DEEBC1C33183A07C70BB18EA2" xlink:to="loc_saic_EarningsPerShareTable_782A68842C5935E63F4307C70BAD3971" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_DC49B63DBD534E49FEC507C70BAE0A92" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_EarningsPerShareTable_782A68842C5935E63F4307C70BAD3971" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_DC49B63DBD534E49FEC507C70BAE0A92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_6540E7C9DB66F2E135FF07C70BAEE450_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_DC49B63DBD534E49FEC507C70BAE0A92" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_6540E7C9DB66F2E135FF07C70BAEE450_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_6540E7C9DB66F2E135FF07C70BAEE450" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_DC49B63DBD534E49FEC507C70BAE0A92" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_6540E7C9DB66F2E135FF07C70BAEE450" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_StockRepurchasePlanMember" xlink:label="loc_saic_StockRepurchasePlanMember_3548B0D9F82F9C1E213C07C70BAE6FB1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_6540E7C9DB66F2E135FF07C70BAEE450" xlink:to="loc_saic_StockRepurchasePlanMember_3548B0D9F82F9C1E213C07C70BAE6FB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_D0F92BEA852C83EC27AB07C70BAF9FC7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_EarningsPerShareTable_782A68842C5935E63F4307C70BAD3971" xlink:to="loc_srt_RangeAxis_D0F92BEA852C83EC27AB07C70BAF9FC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_DD470B30B72CF2A28D8507C70BAF29FB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_D0F92BEA852C83EC27AB07C70BAF9FC7" xlink:to="loc_srt_RangeMember_DD470B30B72CF2A28D8507C70BAF29FB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_DD470B30B72CF2A28D8507C70BAF29FB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_D0F92BEA852C83EC27AB07C70BAF9FC7" xlink:to="loc_srt_RangeMember_DD470B30B72CF2A28D8507C70BAF29FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_B55D8A7C9E0D721A3FDA07C70BAFB8D2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_DD470B30B72CF2A28D8507C70BAF29FB" xlink:to="loc_srt_MaximumMember_B55D8A7C9E0D721A3FDA07C70BAFB8D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsAxis" xlink:label="loc_us-gaap_DividendsAxis_BA9565499E77523B137807C70BB06874" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_EarningsPerShareTable_782A68842C5935E63F4307C70BAD3971" xlink:to="loc_us-gaap_DividendsAxis_BA9565499E77523B137807C70BB06874" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsDomain" xlink:label="loc_us-gaap_DividendsDomain_CB6619148F6573516A9F07C70BB08D72_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DividendsAxis_BA9565499E77523B137807C70BB06874" xlink:to="loc_us-gaap_DividendsDomain_CB6619148F6573516A9F07C70BB08D72_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsDomain" xlink:label="loc_us-gaap_DividendsDomain_CB6619148F6573516A9F07C70BB08D72" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DividendsAxis_BA9565499E77523B137807C70BB06874" xlink:to="loc_us-gaap_DividendsDomain_CB6619148F6573516A9F07C70BB08D72" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_QuarterlyDividendMember" xlink:label="loc_saic_QuarterlyDividendMember_076F17FAAF3576DDA63C07C70BB0F1A0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_CB6619148F6573516A9F07C70BB08D72" xlink:to="loc_saic_QuarterlyDividendMember_076F17FAAF3576DDA63C07C70BB0F1A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_58C6AD0A840EADC5A5EE07C70BB0194E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_EarningsPerShareTable_782A68842C5935E63F4307C70BAD3971" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_58C6AD0A840EADC5A5EE07C70BB0194E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_E6A8ADC57E2FEA7D844307C70BB1241B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_58C6AD0A840EADC5A5EE07C70BB0194E" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_E6A8ADC57E2FEA7D844307C70BB1241B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_E6A8ADC57E2FEA7D844307C70BB1241B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_58C6AD0A840EADC5A5EE07C70BB0194E" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_E6A8ADC57E2FEA7D844307C70BB1241B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_1639D0F6730822AA167007C70BB1CB28" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_E6A8ADC57E2FEA7D844307C70BB1241B" xlink:to="loc_us-gaap_SubsequentEventMember_1639D0F6730822AA167007C70BB1CB28" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_StockRepurchaseProgramIncreaseInNumberOfSharesAuthorizedToBeRepurchased" xlink:label="loc_saic_StockRepurchaseProgramIncreaseInNumberOfSharesAuthorizedToBeRepurchased_86EC2A685C90B687C51507C70BB1A3FA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_7E538F0DEEBC1C33183A07C70BB18EA2" xlink:to="loc_saic_StockRepurchaseProgramIncreaseInNumberOfSharesAuthorizedToBeRepurchased_86EC2A685C90B687C51507C70BB1A3FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:label="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_2E4CE124326A8E4BCE5107C70BB2F775" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_7E538F0DEEBC1C33183A07C70BB18EA2" xlink:to="loc_us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_2E4CE124326A8E4BCE5107C70BB2F775" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_StockRepurchasedAndRetiredUnderAuthorization" xlink:label="loc_saic_StockRepurchasedAndRetiredUnderAuthorization_98D1EAAB94DA5BF93D5907C70BB2CBEB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_7E538F0DEEBC1C33183A07C70BB18EA2" xlink:to="loc_saic_StockRepurchasedAndRetiredUnderAuthorization_98D1EAAB94DA5BF93D5907C70BB2CBEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockDividendsPerShareCashPaid" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_EA7BB421F7FE6133556D07C70BB21C65" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_7E538F0DEEBC1C33183A07C70BB18EA2" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_EA7BB421F7FE6133556D07C70BB21C65" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_2CA4264DE235B971E79A07C70BB2B1D2" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_7E538F0DEEBC1C33183A07C70BB18EA2" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_2CA4264DE235B971E79A07C70BB2B1D2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividendsScheduleOfWeightedAverageSharesOutstandingDetails" xlink:type="extended">
    <link:loc xlink:href="saic-20200131.xsd#saic_ComputationOfEarningsPerShareLineItems" xlink:label="loc_saic_ComputationOfEarningsPerShareLineItems_6493D50499593C9B3E9716D2AAB7CC75" xlink:type="locator" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EarningsPerShareTable" xlink:label="loc_saic_EarningsPerShareTable_589FDEB0FD783AA677F816D2AAB67915" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_6493D50499593C9B3E9716D2AAB7CC75" xlink:to="loc_saic_EarningsPerShareTable_589FDEB0FD783AA677F816D2AAB67915" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_F4B3F5C86D144203ADDC16D2AAB6A041" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_EarningsPerShareTable_589FDEB0FD783AA677F816D2AAB67915" xlink:to="loc_us-gaap_AwardTypeAxis_F4B3F5C86D144203ADDC16D2AAB6A041" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D33826472DA5C53282C516D2AAB6547C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_F4B3F5C86D144203ADDC16D2AAB6A041" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D33826472DA5C53282C516D2AAB6547C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D33826472DA5C53282C516D2AAB6547C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_F4B3F5C86D144203ADDC16D2AAB6A041" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D33826472DA5C53282C516D2AAB6547C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_3D9EA19674B48BAB67E816D2AAB78755" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_D33826472DA5C53282C516D2AAB6547C" xlink:to="loc_us-gaap_EmployeeStockOptionMember_3D9EA19674B48BAB67E816D2AAB78755" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_3968872533546181368716D2AAB7C6F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_6493D50499593C9B3E9716D2AAB7CC75" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_3968872533546181368716D2AAB7C6F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_ECBD5101093B7DD7D68116D2AAB8EE63" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_6493D50499593C9B3E9716D2AAB7CC75" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_ECBD5101093B7DD7D68116D2AAB8EE63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_AD4739F51766B68442FF16D2AAB8FCDB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_6493D50499593C9B3E9716D2AAB7CC75" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_AD4739F51766B68442FF16D2AAB8FCDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_1BB1640DA3D548C1BE3E16D2AAB8EA4B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ComputationOfEarningsPerShareLineItems_6493D50499593C9B3E9716D2AAB7CC75" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_1BB1640DA3D548C1BE3E16D2AAB8EA4B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EarningsPerShareShareRepurchasesAndDividendsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisition" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisitionFairValueOfIntangibleAssetsAndRelatedWeightedAverageUsefulLivesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_FCD358E873D88C173C15B0151D31D739" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5CBF0608EB0B0762BB98B0151D31D851" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FCD358E873D88C173C15B0151D31D739" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5CBF0608EB0B0762BB98B0151D31D851" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_E4E785633CF960B16756B0151D31F24F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5CBF0608EB0B0762BB98B0151D31D851" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_E4E785633CF960B16756B0151D31F24F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_214515808334D0F4A81EB0151D31D27F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_E4E785633CF960B16756B0151D31F24F" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_214515808334D0F4A81EB0151D31D27F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_214515808334D0F4A81EB0151D31D27F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_E4E785633CF960B16756B0151D31F24F" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_214515808334D0F4A81EB0151D31D27F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrderOrProductionBacklogMember" xlink:label="loc_us-gaap_OrderOrProductionBacklogMember_FC9EF2E6CECD6F5E67C7B0151D316600" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_214515808334D0F4A81EB0151D31D27F" xlink:to="loc_us-gaap_OrderOrProductionBacklogMember_FC9EF2E6CECD6F5E67C7B0151D316600" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TechnologyBasedIntangibleAssetsMember" xlink:label="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_0BB6D22E46E3F91F5C1FB0151D31A801" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_214515808334D0F4A81EB0151D31D27F" xlink:to="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_0BB6D22E46E3F91F5C1FB0151D31A801" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_775A47925C9D4048F897B0151D31A22B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_214515808334D0F4A81EB0151D31D27F" xlink:to="loc_us-gaap_CustomerRelationshipsMember_775A47925C9D4048F897B0151D31A22B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_0DCB35F0649AFA8E7218B0151D312B4D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5CBF0608EB0B0762BB98B0151D31D851" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_0DCB35F0649AFA8E7218B0151D312B4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AB2F9C24012DC3B02A2FB0151D317B18_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0DCB35F0649AFA8E7218B0151D312B4D" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AB2F9C24012DC3B02A2FB0151D317B18_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AB2F9C24012DC3B02A2FB0151D317B18" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0DCB35F0649AFA8E7218B0151D312B4D" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AB2F9C24012DC3B02A2FB0151D317B18" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EngilityHoldingsIncMember" xlink:label="loc_saic_EngilityHoldingsIncMember_92190B525F39C32F867AB0151D31E2A0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_AB2F9C24012DC3B02A2FB0151D317B18" xlink:to="loc_saic_EngilityHoldingsIncMember_92190B525F39C32F867AB0151D31E2A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_9ADDEB36C68EB6040DB9B0151D3114F5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FCD358E873D88C173C15B0151D31D739" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_9ADDEB36C68EB6040DB9B0151D3114F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_8CBD1F899FE01C7D928CB0151D317C1D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_FCD358E873D88C173C15B0151D31D739" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_8CBD1F899FE01C7D928CB0151D317C1D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisitionFairValuesOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B074FA06543B8B00D3AB0151D12D311" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B074FA06543B8B00D3AB0151D12D311" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_E62995DDFC7C60BCE600B0151D12AA75" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0B074FA06543B8B00D3AB0151D12D311" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_E62995DDFC7C60BCE600B0151D12AA75" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6086EC07AAEF3B9AE98DB0151D1216AC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_E62995DDFC7C60BCE600B0151D12AA75" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6086EC07AAEF3B9AE98DB0151D1216AC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6086EC07AAEF3B9AE98DB0151D1216AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_E62995DDFC7C60BCE600B0151D12AA75" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6086EC07AAEF3B9AE98DB0151D1216AC" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EngilityHoldingsIncMember" xlink:label="loc_saic_EngilityHoldingsIncMember_9B2C0B713C3636DA1FFFB0151D125F29" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6086EC07AAEF3B9AE98DB0151D1216AC" xlink:to="loc_saic_EngilityHoldingsIncMember_9B2C0B713C3636DA1FFFB0151D125F29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_596314051AFB199BC68DB0151D12C107" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_596314051AFB199BC68DB0151D12C107" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_B18E7188E4ED6E0A5049B0151D12D1F0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_B18E7188E4ED6E0A5049B0151D12D1F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_77A22E9B837117B6CC4BB0151D1260E2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_77A22E9B837117B6CC4BB0151D1260E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_6D05BA373DE0BCCF39ACB0151D124B7C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_6D05BA373DE0BCCF39ACB0151D124B7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_205352FBF73A288C9B9FB0151D12F02E" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_205352FBF73A288C9B9FB0151D12F02E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_692FF9B6C8FE888CEFD4B0151D123072" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_692FF9B6C8FE888CEFD4B0151D123072" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets_CD4F09A1CDBAC85EAA6EB0151D12181C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets_CD4F09A1CDBAC85EAA6EB0151D12181C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_BFD24E8D53EF45073AADB0151D12AFB9" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_BFD24E8D53EF45073AADB0151D12AFB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_53A30073E0C0ABB6BE25B0151D124141" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_53A30073E0C0ABB6BE25B0151D124141" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_3E6ECCDFF3A47BAD50D9B0151D120421" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_Goodwill_3E6ECCDFF3A47BAD50D9B0151D120421" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedAssetsIncludingGoodwill" xlink:label="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedAssetsIncludingGoodwill_4DDEDBD9E616B3DA84A6B0151D12E30A" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedAssetsIncludingGoodwill_4DDEDBD9E616B3DA84A6B0151D12E30A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_08CC39A6E24E3C96B603B0151D1236DC" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_08CC39A6E24E3C96B603B0151D1236DC" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedPayrollAndEmployeeBenefits" xlink:label="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedPayrollAndEmployeeBenefits_2E8317609963B0216EFAB0151D1288EA" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedPayrollAndEmployeeBenefits_2E8317609963B0216EFAB0151D1288EA" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedLiabilitiesAccruedVacation" xlink:label="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedLiabilitiesAccruedVacation_505C034D69AD20DFD1DDB0151D12F9DF" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedLiabilitiesAccruedVacation_505C034D69AD20DFD1DDB0151D12F9DF" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedLiabilitiesOtherAccrued" xlink:label="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedLiabilitiesOtherAccrued_5B3E0197ABABB71596ACB0151D12B5CB" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_saic_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedLiabilitiesOtherAccrued_5B3E0197ABABB71596ACB0151D12B5CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_BDFF161184A62A36A6BCB0151D120C9D" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_BDFF161184A62A36A6BCB0151D120C9D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_C6F0E27038BE64AFCA2DB0151D12C276" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_C6F0E27038BE64AFCA2DB0151D12C276" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_555723E08FEF492E95EFB0151D12B9B2" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_555723E08FEF492E95EFB0151D12B9B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest_7D793547E933B84F4E93B0151D123B9F" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest_7D793547E933B84F4E93B0151D123B9F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" xlink:label="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_C4ABCE6768736CDAE74AB0151D1252A8" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3DC8E2A0E70D4017C255B0151D12A393" xlink:to="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_C4ABCE6768736CDAE74AB0151D1252A8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisitionNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_44B27FC12F0067312E97084EB3B1BEE7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_44B27FC12F0067312E97084EB3B1BEE7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_F75A1093B18CBCB59F90084EB3B2D1FD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_44B27FC12F0067312E97084EB3B1BEE7" xlink:to="loc_us-gaap_DebtInstrumentAxis_F75A1093B18CBCB59F90084EB3B2D1FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7AEF027430289899A249084EB3B3C2D7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_F75A1093B18CBCB59F90084EB3B2D1FD" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7AEF027430289899A249084EB3B3C2D7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_7AEF027430289899A249084EB3B3C2D7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_F75A1093B18CBCB59F90084EB3B2D1FD" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_7AEF027430289899A249084EB3B3C2D7" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TermLoanAFacilityDueOctoberTwoThousandTwentyThreeMember" xlink:label="loc_saic_TermLoanAFacilityDueOctoberTwoThousandTwentyThreeMember_C9B69508B88433A68256084EB3B3284B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_7AEF027430289899A249084EB3B3C2D7" xlink:to="loc_saic_TermLoanAFacilityDueOctoberTwoThousandTwentyThreeMember_C9B69508B88433A68256084EB3B3284B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_CA74340BC7E6D971F150084EB3B3D235" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_44B27FC12F0067312E97084EB3B1BEE7" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_CA74340BC7E6D971F150084EB3B3D235" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_C53B40965B00D008FAEF084EB3B30CD6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CA74340BC7E6D971F150084EB3B3D235" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_C53B40965B00D008FAEF084EB3B30CD6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_C53B40965B00D008FAEF084EB3B30CD6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_CA74340BC7E6D971F150084EB3B3D235" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_C53B40965B00D008FAEF084EB3B30CD6" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ThirdAmendedCreditAgreementMember" xlink:label="loc_saic_ThirdAmendedCreditAgreementMember_717B4972F5FE81F68AF5084EB3B35F1E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_C53B40965B00D008FAEF084EB3B30CD6" xlink:to="loc_saic_ThirdAmendedCreditAgreementMember_717B4972F5FE81F68AF5084EB3B35F1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_0E131B3281C224B65673084EB3B4402E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_44B27FC12F0067312E97084EB3B1BEE7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_0E131B3281C224B65673084EB3B4402E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6D1C1747561464CA5345084EB3B4C306_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0E131B3281C224B65673084EB3B4402E" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6D1C1747561464CA5345084EB3B4C306_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6D1C1747561464CA5345084EB3B4C306" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0E131B3281C224B65673084EB3B4402E" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6D1C1747561464CA5345084EB3B4C306" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EngilityHoldingsIncMember" xlink:label="loc_saic_EngilityHoldingsIncMember_47FB31DEE10EFB8BB21D084EB3B4194C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6D1C1747561464CA5345084EB3B4C306" xlink:to="loc_saic_EngilityHoldingsIncMember_47FB31DEE10EFB8BB21D084EB3B4194C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationEquityRightConversionCommonSharesConversionRatio" xlink:label="loc_saic_BusinessCombinationEquityRightConversionCommonSharesConversionRatio_B5405FBD07940E81664D084EB3B5EFE1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_saic_BusinessCombinationEquityRightConversionCommonSharesConversionRatio_B5405FBD07940E81664D084EB3B5EFE1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="loc_us-gaap_DebtInstrumentTerm_B9335C3E5A4B1181F59D084EB3B57B11" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_DebtInstrumentTerm_B9335C3E5A4B1181F59D084EB3B57B11" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_2543A39632D6E471285B084EB3B569EA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_2543A39632D6E471285B084EB3B569EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_732325E76854B9282709084EB3B528F5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_732325E76854B9282709084EB3B528F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_284EA934FD5361E83BC5084EB3B6A379" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_284EA934FD5361E83BC5084EB3B6A379" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentInventory" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentInventory_D62E01379E5F62CDF24B084EB3B6A67F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentInventory_D62E01379E5F62CDF24B084EB3B6A67F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentReceivables" xlink:label="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentReceivables_40A049A9AE131CB9350B084EB3B6D301" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentReceivables_40A049A9AE131CB9350B084EB3B6D301" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_9694C48EB1E14B6ECC38084EB3B64C8E" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_9694C48EB1E14B6ECC38084EB3B64C8E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_35836D2D07DFAAC5DAAE084EB3B62045" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_35836D2D07DFAAC5DAAE084EB3B62045" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_2601605CE65E4ED3DAFD084EB3B7D679" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_2601605CE65E4ED3DAFD084EB3B7D679" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationIntegrationRelatedCosts_250C7D6B0AE9ABC5339F084EB3B708F7" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_BusinessCombinationIntegrationRelatedCosts_250C7D6B0AE9ABC5339F084EB3B708F7" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxAssets" xlink:label="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxAssets_8C97B288421BCF0ABE71084EB3B7EB07" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxAssets_8C97B288421BCF0ABE71084EB3B7EB07" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentAssets" xlink:label="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentAssets_8A373D34EE4A51C1C181084EB3B7697E" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherCurrentAssets_8A373D34EE4A51C1C181084EB3B7697E" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherAccruedLiabilities" xlink:label="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherAccruedLiabilities_2CD51A4873C78E9D6A33084EB3B7D30D" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentOtherAccruedLiabilities_2CD51A4873C78E9D6A33084EB3B7D30D" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts" xlink:label="loc_saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts_900594D817A42CC91571084EB3B80FD8" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts_900594D817A42CC91571084EB3B80FD8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual" xlink:label="loc_us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual_42537C6C2873A31B4C2F084EB3B83EC7" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual_42537C6C2873A31B4C2F084EB3B83EC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual" xlink:label="loc_us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual_284C2ED73ADA6D1E9F00084EB3B8FA20" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual_284C2ED73ADA6D1E9F00084EB3B8FA20" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationProFormaInformationIntegrationRelatedCosts" xlink:label="loc_saic_BusinessCombinationProFormaInformationIntegrationRelatedCosts_479C967E30DCDA274396084EB3B8021E" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_35EEA93C423851D8E728084EB3B55624" xlink:to="loc_saic_BusinessCombinationProFormaInformationIntegrationRelatedCosts_479C967E30DCDA274396084EB3B8021E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisitionProFormaDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_DD52D3C29B978255864EB0151B9B9D45" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9C56962B2A675B71B018B0151B9B8655" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_DD52D3C29B978255864EB0151B9B9D45" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9C56962B2A675B71B018B0151B9B8655" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_82866FC4EBA1046CE0CCB0151B9B8849" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9C56962B2A675B71B018B0151B9B8655" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_82866FC4EBA1046CE0CCB0151B9B8849" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_160096B13AEBF669B94CB0151B9BA896_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_82866FC4EBA1046CE0CCB0151B9B8849" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_160096B13AEBF669B94CB0151B9BA896_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_160096B13AEBF669B94CB0151B9BA896" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_82866FC4EBA1046CE0CCB0151B9B8849" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_160096B13AEBF669B94CB0151B9BA896" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EngilityHoldingsIncMember" xlink:label="loc_saic_EngilityHoldingsIncMember_B145E08E8EF884F14E05B0151B9BCC28" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_160096B13AEBF669B94CB0151B9BA896" xlink:to="loc_saic_EngilityHoldingsIncMember_B145E08E8EF884F14E05B0151B9BCC28" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_4874D6B92A8BF50F18E5B0151B9BBDE8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_DD52D3C29B978255864EB0151B9B9D45" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_4874D6B92A8BF50F18E5B0151B9BBDE8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_4049164B86B77A2D34FAB0151B9BAEE6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_DD52D3C29B978255864EB0151B9B9D45" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_4049164B86B77A2D34FAB0151B9BAEE6" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisitionScheduleOfAcquisitionAndIntegrationCostsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_5EAE298EC163F0EE36B108302D315B70" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_73B5EFF8ACA190B9235B08302D28E9D2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5EAE298EC163F0EE36B108302D315B70" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_73B5EFF8ACA190B9235B08302D28E9D2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_298415346BFF5E00938C08302D29A35E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_73B5EFF8ACA190B9235B08302D28E9D2" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_298415346BFF5E00938C08302D29A35E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BF18C271B9AAD3EFF62E08302D2AA79A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_298415346BFF5E00938C08302D29A35E" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BF18C271B9AAD3EFF62E08302D2AA79A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BF18C271B9AAD3EFF62E08302D2AA79A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_298415346BFF5E00938C08302D29A35E" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_BF18C271B9AAD3EFF62E08302D2AA79A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_9545A9663E7022B6F5E908302D2B50D5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_73B5EFF8ACA190B9235B08302D28E9D2" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_9545A9663E7022B6F5E908302D2B50D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_135A3518468F95117E8108302D2C3252_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9545A9663E7022B6F5E908302D2B50D5" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_135A3518468F95117E8108302D2C3252_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_135A3518468F95117E8108302D2C3252" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9545A9663E7022B6F5E908302D2B50D5" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_135A3518468F95117E8108302D2C3252" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_OwnershipAxis" xlink:label="loc_srt_OwnershipAxis_468D4A2B5AA7CA16A98B08302D2D22AD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_73B5EFF8ACA190B9235B08302D28E9D2" xlink:to="loc_srt_OwnershipAxis_468D4A2B5AA7CA16A98B08302D2D22AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_OwnershipDomain" xlink:label="loc_srt_OwnershipDomain_37003C07101C91921E7508302D2E46B3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_468D4A2B5AA7CA16A98B08302D2D22AD" xlink:to="loc_srt_OwnershipDomain_37003C07101C91921E7508302D2E46B3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_OwnershipDomain" xlink:label="loc_srt_OwnershipDomain_37003C07101C91921E7508302D2E46B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_468D4A2B5AA7CA16A98B08302D2D22AD" xlink:to="loc_srt_OwnershipDomain_37003C07101C91921E7508302D2E46B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_4274BC1B159BD9667FFC08302D2F5F3D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_73B5EFF8ACA190B9235B08302D28E9D2" xlink:to="loc_us-gaap_StatementClassOfStockAxis_4274BC1B159BD9667FFC08302D2F5F3D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_4C7527265EBB7BF389C308302D30310E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4274BC1B159BD9667FFC08302D2F5F3D" xlink:to="loc_us-gaap_ClassOfStockDomain_4C7527265EBB7BF389C308302D30310E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_4C7527265EBB7BF389C308302D30310E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4274BC1B159BD9667FFC08302D2F5F3D" xlink:to="loc_us-gaap_ClassOfStockDomain_4C7527265EBB7BF389C308302D30310E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_490BEAB2CBB3B9CB87400832403FBED2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5EAE298EC163F0EE36B108302D315B70" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_490BEAB2CBB3B9CB87400832403FBED2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:label="loc_us-gaap_BusinessCombinationIntegrationRelatedCosts_8798060351E2A35C238208338ED2C4DB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5EAE298EC163F0EE36B108302D315B70" xlink:to="loc_us-gaap_BusinessCombinationIntegrationRelatedCosts_8798060351E2A35C238208338ED2C4DB" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts" xlink:label="loc_saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts_CE6A4E17C1417E86168D083480C524F5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5EAE298EC163F0EE36B108302D315B70" xlink:to="loc_saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts_CE6A4E17C1417E86168D083480C524F5" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationAcquisitionandIntegrationCostsRestructuringExpense" xlink:label="loc_saic_BusinessCombinationAcquisitionandIntegrationCostsRestructuringExpense_7716D5F439F46D57DB53083A7904DAC8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5EAE298EC163F0EE36B108302D315B70" xlink:to="loc_saic_BusinessCombinationAcquisitionandIntegrationCostsRestructuringExpense_7716D5F439F46D57DB53083A7904DAC8" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_OperatingLeaseRightofUseAssetImpairment" xlink:label="loc_saic_OperatingLeaseRightofUseAssetImpairment_306B1C74539B6340DC7D083998968A58" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5EAE298EC163F0EE36B108302D315B70" xlink:to="loc_saic_OperatingLeaseRightofUseAssetImpairment_306B1C74539B6340DC7D083998968A58" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisitionSummaryOfPreliminaryPurchaseConsiderationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_3113E2BB97C8C7DCB5AAB0151C858BC8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_710E14D763554984DD0FB0151C85A79D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3113E2BB97C8C7DCB5AAB0151C858BC8" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_710E14D763554984DD0FB0151C85A79D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_13CB468F769B626AC89AB0151C85A4A6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_710E14D763554984DD0FB0151C85A79D" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_13CB468F769B626AC89AB0151C85A4A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2C474B05439515814A4BB0151C85A0AF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_13CB468F769B626AC89AB0151C85A4A6" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2C474B05439515814A4BB0151C85A0AF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2C474B05439515814A4BB0151C85A0AF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_13CB468F769B626AC89AB0151C85A4A6" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2C474B05439515814A4BB0151C85A0AF" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EngilityHoldingsIncMember" xlink:label="loc_saic_EngilityHoldingsIncMember_9281675BD4462440D8BEB0151C85F0CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_2C474B05439515814A4BB0151C85A0AF" xlink:to="loc_saic_EngilityHoldingsIncMember_9281675BD4462440D8BEB0151C85F0CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_05E1E16051FC1AC75DEEB0151C85A1A7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_710E14D763554984DD0FB0151C85A79D" xlink:to="loc_us-gaap_AwardTypeAxis_05E1E16051FC1AC75DEEB0151C85A1A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_63E82B84A568E6CC8D8AB0151C85E91A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_05E1E16051FC1AC75DEEB0151C85A1A7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_63E82B84A568E6CC8D8AB0151C85E91A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_63E82B84A568E6CC8D8AB0151C85E91A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_05E1E16051FC1AC75DEEB0151C85A1A7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_63E82B84A568E6CC8D8AB0151C85E91A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_482D27A2F0C27EA2C786B0151C859321" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_63E82B84A568E6CC8D8AB0151C85E91A" xlink:to="loc_us-gaap_RestrictedStockMember_482D27A2F0C27EA2C786B0151C859321" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_04E6F02618618E9F481AB0151C85ECE9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_710E14D763554984DD0FB0151C85A79D" xlink:to="loc_us-gaap_StatementClassOfStockAxis_04E6F02618618E9F481AB0151C85ECE9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_67ADA806F3F364D4477AB0151C859BB9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_04E6F02618618E9F481AB0151C85ECE9" xlink:to="loc_us-gaap_ClassOfStockDomain_67ADA806F3F364D4477AB0151C859BB9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_67ADA806F3F364D4477AB0151C859BB9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_04E6F02618618E9F481AB0151C85ECE9" xlink:to="loc_us-gaap_ClassOfStockDomain_67ADA806F3F364D4477AB0151C859BB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_FF529B5EDF619EF75C85B0151C854800" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_67ADA806F3F364D4477AB0151C859BB9" xlink:to="loc_us-gaap_CommonStockMember_FF529B5EDF619EF75C85B0151C854800" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_C873FA1B4A1CC2FB3775B0151C8530E0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3113E2BB97C8C7DCB5AAB0151C858BC8" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_C873FA1B4A1CC2FB3775B0151C8530E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_5F1FFF6B9D339C68E9B6B0151C8503B8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3113E2BB97C8C7DCB5AAB0151C858BC8" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_5F1FFF6B9D339C68E9B6B0151C8503B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_67E05824E5A70E3DB845B0151C85CC87" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3113E2BB97C8C7DCB5AAB0151C858BC8" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_67E05824E5A70E3DB845B0151C85CC87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued" xlink:label="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_5CB4B6EAAB83F1EC317CB0151C85A450" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3113E2BB97C8C7DCB5AAB0151C858BC8" xlink:to="loc_us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued_5CB4B6EAAB83F1EC317CB0151C85A450" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionSharePrice" xlink:label="loc_us-gaap_BusinessAcquisitionSharePrice_91EA3251FCAA601264C3B0151C853CAF" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_3113E2BB97C8C7DCB5AAB0151C858BC8" xlink:to="loc_us-gaap_BusinessAcquisitionSharePrice_91EA3251FCAA601264C3B0151C853CAF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/EngilityAcquisitionTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/GoodwillAndIntangibleAssets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/GoodwillAndIntangibleAssetsEstimatedAnnualAmortizationExpenseDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/GoodwillAndIntangibleAssetsNarrativeDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/GoodwillAndIntangibleAssetsScheduleOfIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_53D8268F295437FC66C511D7931FC9E4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_685FB831B3EF015B5BCC11D7931F3E0D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_53D8268F295437FC66C511D7931FC9E4" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_685FB831B3EF015B5BCC11D7931F3E0D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BCDC831D7C18148F08511D7931F2889" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_685FB831B3EF015B5BCC11D7931F3E0D" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BCDC831D7C18148F08511D7931F2889" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_E2160FE19B71E64E39A311D7931FDCC4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BCDC831D7C18148F08511D7931F2889" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_E2160FE19B71E64E39A311D7931FDCC4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_E2160FE19B71E64E39A311D7931FDCC4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_8BCDC831D7C18148F08511D7931F2889" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_E2160FE19B71E64E39A311D7931FDCC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="loc_us-gaap_CustomerRelationshipsMember_FE8C4CC43EEDB56EFB9611D7931FAA4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_E2160FE19B71E64E39A311D7931FDCC4" xlink:to="loc_us-gaap_CustomerRelationshipsMember_FE8C4CC43EEDB56EFB9611D7931FAA4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrderOrProductionBacklogMember" xlink:label="loc_us-gaap_OrderOrProductionBacklogMember_F204785780697702806F11D7931F341B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_E2160FE19B71E64E39A311D7931FDCC4" xlink:to="loc_us-gaap_OrderOrProductionBacklogMember_F204785780697702806F11D7931F341B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TechnologyBasedIntangibleAssetsMember" xlink:label="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_2E8ED7D843C4EF9B2BE611D7931F920E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_E2160FE19B71E64E39A311D7931FDCC4" xlink:to="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_2E8ED7D843C4EF9B2BE611D7931F920E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_8B706BA0EEE86CBBEA1011D7931FD021" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_53D8268F295437FC66C511D7931FC9E4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_8B706BA0EEE86CBBEA1011D7931FD021" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_05DEC33E40786C293CE811D7931F1A64" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_53D8268F295437FC66C511D7931FC9E4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_05DEC33E40786C293CE811D7931F1A64" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_E3771CBFD225554A08C211D7931F121C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_53D8268F295437FC66C511D7931FC9E4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_E3771CBFD225554A08C211D7931F121C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/GoodwillAndIntangibleAssetsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/IncomeTaxes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="saic-20200131.xsd#saic_IncomeTaxesLineItems" xlink:label="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:type="locator" />
    <link:loc xlink:href="saic-20200131.xsd#saic_IncomeTaxesTable" xlink:label="loc_saic_IncomeTaxesTable_7F73F69CCF17D8A5EB2C0D0BB6388278" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_saic_IncomeTaxesTable_7F73F69CCF17D8A5EB2C0D0BB6388278" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:label="loc_us-gaap_TaxPeriodAxis_539736AEB075CAF44E380D0BF5C6937C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_IncomeTaxesTable_7F73F69CCF17D8A5EB2C0D0BB6388278" xlink:to="loc_us-gaap_TaxPeriodAxis_539736AEB075CAF44E380D0BF5C6937C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_FC9762289367A73A47030D0C31E34B71_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_539736AEB075CAF44E380D0BF5C6937C" xlink:to="loc_us-gaap_TaxPeriodDomain_FC9762289367A73A47030D0C31E34B71_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_FC9762289367A73A47030D0C31E34B71" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_539736AEB075CAF44E380D0BF5C6937C" xlink:to="loc_us-gaap_TaxPeriodDomain_FC9762289367A73A47030D0C31E34B71" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TaxYear20162019Member" xlink:label="loc_saic_TaxYear20162019Member_8C66CE1277158C3015260D0CCC5C63D8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_FC9762289367A73A47030D0C31E34B71" xlink:to="loc_saic_TaxYear20162019Member_8C66CE1277158C3015260D0CCC5C63D8" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TaxYear2020Member" xlink:label="loc_saic_TaxYear2020Member_21199E1C248853D361E00D0D5BDA3059" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_FC9762289367A73A47030D0C31E34B71" xlink:to="loc_saic_TaxYear2020Member_21199E1C248853D361E00D0D5BDA3059" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_68A5DD68AA7A59689FC40D0BB63A8178" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_IncomeTaxesTable_7F73F69CCF17D8A5EB2C0D0BB6388278" xlink:to="loc_srt_RangeAxis_68A5DD68AA7A59689FC40D0BB63A8178" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_3E5A7DA500FD5DB03B190D0BB63AF6C1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_68A5DD68AA7A59689FC40D0BB63A8178" xlink:to="loc_srt_RangeMember_3E5A7DA500FD5DB03B190D0BB63AF6C1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_3E5A7DA500FD5DB03B190D0BB63AF6C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_68A5DD68AA7A59689FC40D0BB63A8178" xlink:to="loc_srt_RangeMember_3E5A7DA500FD5DB03B190D0BB63AF6C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_93E6C70258DDCB07C9200D0BB63F4CD1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3E5A7DA500FD5DB03B190D0BB63AF6C1" xlink:to="loc_srt_MinimumMember_93E6C70258DDCB07C9200D0BB63F4CD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_98FD94BF54645E6F05180D0BB63FD6F8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3E5A7DA500FD5DB03B190D0BB63AF6C1" xlink:to="loc_srt_MaximumMember_98FD94BF54645E6F05180D0BB63FD6F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_863F40F5CB74515FAF9A0D0BB640A063" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_IncomeTaxesTable_7F73F69CCF17D8A5EB2C0D0BB6388278" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_863F40F5CB74515FAF9A0D0BB640A063" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_7F865CE80D34E7F149A50D0BB6407388_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_863F40F5CB74515FAF9A0D0BB640A063" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_7F865CE80D34E7F149A50D0BB6407388_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_7F865CE80D34E7F149A50D0BB6407388" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_863F40F5CB74515FAF9A0D0BB640A063" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_7F865CE80D34E7F149A50D0BB6407388" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DomesticCountryMember" xlink:label="loc_us-gaap_DomesticCountryMember_4AA8A1B0FEBAF2A9A5F70D0BB640FE66" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_7F865CE80D34E7F149A50D0BB6407388" xlink:to="loc_us-gaap_DomesticCountryMember_4AA8A1B0FEBAF2A9A5F70D0BB640FE66" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_9854C2434BD233A4B8240D0BB6411F47" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_7F865CE80D34E7F149A50D0BB6407388" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_9854C2434BD233A4B8240D0BB6411F47" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_DBE838FFC1C9EE31E3EC0D0BB641E691" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_IncomeTaxesTable_7F73F69CCF17D8A5EB2C0D0BB6388278" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_DBE838FFC1C9EE31E3EC0D0BB641E691" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ACD53147C57D49A6AAA20D0BB6410498_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_DBE838FFC1C9EE31E3EC0D0BB641E691" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ACD53147C57D49A6AAA20D0BB6410498_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ACD53147C57D49A6AAA20D0BB6410498" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_DBE838FFC1C9EE31E3EC0D0BB641E691" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ACD53147C57D49A6AAA20D0BB6410498" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ScitorHoldingsIncMember" xlink:label="loc_saic_ScitorHoldingsIncMember_DC7E7899F3B86B119E890D0BB6410BB8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ACD53147C57D49A6AAA20D0BB6410498" xlink:to="loc_saic_ScitorHoldingsIncMember_DC7E7899F3B86B119E890D0BB6410BB8" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EngilityHoldingsIncMember" xlink:label="loc_saic_EngilityHoldingsIncMember_11111E929614CF8120760D0BB64208E5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ACD53147C57D49A6AAA20D0BB6410498" xlink:to="loc_saic_EngilityHoldingsIncMember_11111E929614CF8120760D0BB64208E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxReconciliationTaxCreditsResearch" xlink:label="loc_us-gaap_IncomeTaxReconciliationTaxCreditsResearch_9E422C47F7EE0A9289F10D0D84136A6B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_IncomeTaxReconciliationTaxCreditsResearch_9E422C47F7EE0A9289F10D0D84136A6B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpense" xlink:label="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpense_CE8208B3C9CAA7848BF30D0BB6423FD9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_IncomeTaxReconciliationNondeductibleExpense_CE8208B3C9CAA7848BF30D0BB6423FD9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions_5496ECBC62B1B5981E100D135CA4826C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions_5496ECBC62B1B5981E100D135CA4826C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_98C40F7D10C8E7E2B3140D10416CABA0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_98C40F7D10C8E7E2B3140D10416CABA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount" xlink:label="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_4CEC0D3E75AC7A89BA090D0BB643014F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_4CEC0D3E75AC7A89BA090D0BB643014F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessAcquisitionPurchasePriceAllocationIdentifiedIntangibleAssetsExpectedTaxDeductibleAmount" xlink:label="loc_saic_BusinessAcquisitionPurchasePriceAllocationIdentifiedIntangibleAssetsExpectedTaxDeductibleAmount_A46A32C7B01B049EAE6F0D0BB6431A3A" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_saic_BusinessAcquisitionPurchasePriceAllocationIdentifiedIntangibleAssetsExpectedTaxDeductibleAmount_A46A32C7B01B049EAE6F0D0BB6431A3A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_909364CF7FC0542BE4AF0D0BB643906C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_909364CF7FC0542BE4AF0D0BB643906C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentTaxCreditCarryforward" xlink:label="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentTaxCreditCarryforward_0468C26B44A4E904B2160D0BB64492BC" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_saic_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentTaxCreditCarryforward_0468C26B44A4E904B2160D0BB64492BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="loc_us-gaap_OperatingLossCarryforwards_EA9ACCAD60369B358DD00D0BB644D79B" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_OperatingLossCarryforwards_EA9ACCAD60369B358DD00D0BB644D79B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxCreditCarryforwardAmount" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_7ABD9817F3BE141E3ADE0D0BB6448154" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_7ABD9817F3BE141E3ADE0D0BB6448154" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLossCarryforwardsValuationAllowance" xlink:label="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_4FE941BA952F630359750D0BB6446FA6" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_IncomeTaxesLineItems_CB0C7C082BF231E83F9D0D0BB642BA84" xlink:to="loc_us-gaap_OperatingLossCarryforwardsValuationAllowance_4FE941BA952F630359750D0BB6446FA6" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/IncomeTaxesProvisionForIncomeTaxesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/IncomeTaxesReconciliationOfProvisionForIncomeTaxesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/IncomeTaxesScheduleOfChangesInUnrecognizedTaxBenefitsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/IncomeTaxesScheduleOfDeferredTaxAssetsLiabilitiesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/IncomeTaxesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/Leases" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LeasesAssetsAndLiabilitiesLeasesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LeasesLeaseCostDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LeasesNarrativeAsc840Details" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LeasesNarrativeAsc842Details" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_BDFEE72886DA97EE25DEF3328740A5D3" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_EC663D6A4967E720BA52F332873F1DCD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_BDFEE72886DA97EE25DEF3328740A5D3" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_EC663D6A4967E720BA52F332873F1DCD" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseArrangementTypeAxis" xlink:label="loc_us-gaap_LeaseArrangementTypeAxis_DB59576133C44CB28844F33287402CD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_EC663D6A4967E720BA52F332873F1DCD" xlink:to="loc_us-gaap_LeaseArrangementTypeAxis_DB59576133C44CB28844F33287402CD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseArrangementTypeDomain" xlink:label="loc_us-gaap_LeaseArrangementTypeDomain_C78772FE0D9E721FC832F332874044AD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LeaseArrangementTypeAxis_DB59576133C44CB28844F33287402CD2" xlink:to="loc_us-gaap_LeaseArrangementTypeDomain_C78772FE0D9E721FC832F332874044AD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseArrangementTypeDomain" xlink:label="loc_us-gaap_LeaseArrangementTypeDomain_C78772FE0D9E721FC832F332874044AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LeaseArrangementTypeAxis_DB59576133C44CB28844F33287402CD2" xlink:to="loc_us-gaap_LeaseArrangementTypeDomain_C78772FE0D9E721FC832F332874044AD" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_LeaseArrangement1Member" xlink:label="loc_saic_LeaseArrangement1Member_31C44797ABD82C4495B7F33287401DA7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseArrangementTypeDomain_C78772FE0D9E721FC832F332874044AD" xlink:to="loc_saic_LeaseArrangement1Member_31C44797ABD82C4495B7F33287401DA7" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_LesseeOperatingLeaseNotyetCommencedValue" xlink:label="loc_saic_LesseeOperatingLeaseNotyetCommencedValue_D52589E8031FF0E0AF2BF3328741C3F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_BDFEE72886DA97EE25DEF3328740A5D3" xlink:to="loc_saic_LesseeOperatingLeaseNotyetCommencedValue_D52589E8031FF0E0AF2BF3328741C3F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1" xlink:label="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_F9709AB70FDEE9F84B85F3328740334D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_BDFEE72886DA97EE25DEF3328740A5D3" xlink:to="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_F9709AB70FDEE9F84B85F3328740334D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/LeasesOperatingLeaseLiabilitiesPaymentsDueDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LeasesOtherSupplementalLeaseInformationDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LeasesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LegalProceedingsAndCommitmentsAndContingencies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/LegalProceedingsAndCommitmentsAndContingenciesDetails" xlink:type="extended">
    <link:loc xlink:href="saic-20200131.xsd#saic_CommitmentsAndContingenciesLineItems" xlink:label="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:type="locator" />
    <link:loc xlink:href="saic-20200131.xsd#saic_CommitmentsAndContingenciesTable" xlink:label="loc_saic_CommitmentsAndContingenciesTable_439865E598B0304646C4084EB133236D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_saic_CommitmentsAndContingenciesTable_439865E598B0304646C4084EB133236D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_D8349485E5EBB705F430084EB134B644" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_CommitmentsAndContingenciesTable_439865E598B0304646C4084EB133236D" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_D8349485E5EBB705F430084EB134B644" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5DCE9851A05B5CE4CDD4084EB1346374_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_D8349485E5EBB705F430084EB134B644" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5DCE9851A05B5CE4CDD4084EB1346374_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5DCE9851A05B5CE4CDD4084EB1346374" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_D8349485E5EBB705F430084EB134B644" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5DCE9851A05B5CE4CDD4084EB1346374" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ScitorHoldingsIncMember" xlink:label="loc_saic_ScitorHoldingsIncMember_BC3A1354D0B15434675D084EB134E32F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5DCE9851A05B5CE4CDD4084EB1346374" xlink:to="loc_saic_ScitorHoldingsIncMember_BC3A1354D0B15434675D084EB134E32F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_DC45248DB323865E54FB084EB13614A2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_CommitmentsAndContingenciesTable_439865E598B0304646C4084EB133236D" xlink:to="loc_srt_RangeAxis_DC45248DB323865E54FB084EB13614A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_B23EB7CCF60FF8D49E9B084EB136FAC4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_DC45248DB323865E54FB084EB13614A2" xlink:to="loc_srt_RangeMember_B23EB7CCF60FF8D49E9B084EB136FAC4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_B23EB7CCF60FF8D49E9B084EB136FAC4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_DC45248DB323865E54FB084EB13614A2" xlink:to="loc_srt_RangeMember_B23EB7CCF60FF8D49E9B084EB136FAC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_50E5036AD6B190D747BE084EB137DA8E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_B23EB7CCF60FF8D49E9B084EB136FAC4" xlink:to="loc_srt_MinimumMember_50E5036AD6B190D747BE084EB137DA8E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_6A88E03D0C720F36D56F084EB137961C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_saic_CommitmentsAndContingenciesTable_439865E598B0304646C4084EB133236D" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_6A88E03D0C720F36D56F084EB137961C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_5EB4E2CED9D5B6451FB2084EB1371469_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_6A88E03D0C720F36D56F084EB137961C" xlink:to="loc_us-gaap_LossContingencyNatureDomain_5EB4E2CED9D5B6451FB2084EB1371469_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="loc_us-gaap_LossContingencyNatureDomain_5EB4E2CED9D5B6451FB2084EB1371469" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_6A88E03D0C720F36D56F084EB137961C" xlink:to="loc_us-gaap_LossContingencyNatureDomain_5EB4E2CED9D5B6451FB2084EB1371469" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_GovernmentInvestigationsAndReviewsMember" xlink:label="loc_saic_GovernmentInvestigationsAndReviewsMember_CFC0ACAD88B3C0871814084EB1375027" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_5EB4E2CED9D5B6451FB2084EB1371469" xlink:to="loc_saic_GovernmentInvestigationsAndReviewsMember_CFC0ACAD88B3C0871814084EB1375027" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FinancialStandbyLetterOfCreditMember" xlink:label="loc_us-gaap_FinancialStandbyLetterOfCreditMember_0C6B59E219A442AF9348084EB13810D6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_5EB4E2CED9D5B6451FB2084EB1371469" xlink:to="loc_us-gaap_FinancialStandbyLetterOfCreditMember_0C6B59E219A442AF9348084EB13810D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SuretyBondMember" xlink:label="loc_us-gaap_SuretyBondMember_FB0FA49BA8D3F9D5A9D6084EB138103A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingencyNatureDomain_5EB4E2CED9D5B6451FB2084EB1371469" xlink:to="loc_us-gaap_SuretyBondMember_FB0FA49BA8D3F9D5A9D6084EB138103A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_94175C39AEF5DDCFD935084EB13826D4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_94175C39AEF5DDCFD935084EB13826D4" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationAmountDepositedToAdjustmentAndIndemnificationEscrowAccountsIncludedInCashConsiderationPaid" xlink:label="loc_saic_BusinessCombinationAmountDepositedToAdjustmentAndIndemnificationEscrowAccountsIncludedInCashConsiderationPaid_DF056B45A5E8ADE50506084EB1399933" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_saic_BusinessCombinationAmountDepositedToAdjustmentAndIndemnificationEscrowAccountsIncludedInCashConsiderationPaid_DF056B45A5E8ADE50506084EB1399933" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationAmountDepositedToAdjustmentAndIndemnificationEscrowAccountsAmountsReleased" xlink:label="loc_saic_BusinessCombinationAmountDepositedToAdjustmentAndIndemnificationEscrowAccountsAmountsReleased_BDF91EEB07190C249D4A084EB139467D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_saic_BusinessCombinationAmountDepositedToAdjustmentAndIndemnificationEscrowAccountsAmountsReleased_BDF91EEB07190C249D4A084EB139467D" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationEscrowDepositDisbursementsReceived" xlink:label="loc_saic_BusinessCombinationEscrowDepositDisbursementsReceived_E9FBBC9C681394B763B2084EB139B609" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_saic_BusinessCombinationEscrowDepositDisbursementsReceived_E9FBBC9C681394B763B2084EB139B609" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EscrowDeposit" xlink:label="loc_us-gaap_EscrowDeposit_29BE2B6B9569DA81A1A4084EB1396940" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_us-gaap_EscrowDeposit_29BE2B6B9569DA81A1A4084EB1396940" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_644C22E0D00DC33CF3B7084EB13AEDF2" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_644C22E0D00DC33CF3B7084EB13AEDF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:label="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_BA248FBEF1652B4345D8084EB13AAE3C" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_CommitmentsAndContingenciesLineItems_B115DB76A2735E42D3EA084EB1380B8C" xlink:to="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_BA248FBEF1652B4345D8084EB13AAE3C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/PropertyPlantAndEquipment" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/PropertyPlantAndEquipmentNarrativeDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/PropertyPlantAndEquipmentScheduleOfPropertyPlantAndEquipmentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_FC1911047CD5433B778CCE7E9E9A993E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_FC1911047CD5433B778CCE7E9E9A993E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38B1011437DAC5AC14ADCE7E9E9B2789" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_FC1911047CD5433B778CCE7E9E9A993E" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38B1011437DAC5AC14ADCE7E9E9B2789" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38B1011437DAC5AC14ADCE7E9E9B2789" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_38B1011437DAC5AC14ADCE7E9E9B2789" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComputerEquipmentMember" xlink:label="loc_us-gaap_ComputerEquipmentMember_65B18CBB203F2CE12B77CE7E9E9CF912" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:to="loc_us-gaap_ComputerEquipmentMember_65B18CBB203F2CE12B77CE7E9E9CF912" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_EDFCFDEA85DB37B6CDB5CE7E9E9CC487" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:to="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_EDFCFDEA85DB37B6CDB5CE7E9E9CC487" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_258376611664A8DE1629CE7E9E9C503E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_258376611664A8DE1629CE7E9E9C503E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_51BD2A2DEA14358A3F3DCE7E9E9C7983" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_51BD2A2DEA14358A3F3DCE7E9E9C7983" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_A4B860A16B5E8DFC64EECE7E9E9C539E" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_A4B860A16B5E8DFC64EECE7E9E9C539E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConstructionInProgressMember" xlink:label="loc_us-gaap_ConstructionInProgressMember_AAFEF81046E4F09E2A58CE7E9E9D8082" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:to="loc_us-gaap_ConstructionInProgressMember_AAFEF81046E4F09E2A58CE7E9E9D8082" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LandMember" xlink:label="loc_us-gaap_LandMember_5D5330B5921FD9560497CE7E9E9DEA08" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_5ECF760873284456DA27CE7E9E9B0357" xlink:to="loc_us-gaap_LandMember_5D5330B5921FD9560497CE7E9E9DEA08" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_0CD068240FFB06DD5E8BCE7E9E9D2E26" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_FC1911047CD5433B778CCE7E9E9A993E" xlink:to="loc_srt_RangeAxis_0CD068240FFB06DD5E8BCE7E9E9D2E26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_4FE726617ACFEBEF869ECE7E9E9D4BD4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_0CD068240FFB06DD5E8BCE7E9E9D2E26" xlink:to="loc_srt_RangeMember_4FE726617ACFEBEF869ECE7E9E9D4BD4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_4FE726617ACFEBEF869ECE7E9E9D4BD4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_0CD068240FFB06DD5E8BCE7E9E9D2E26" xlink:to="loc_srt_RangeMember_4FE726617ACFEBEF869ECE7E9E9D4BD4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_35C682F7AB8611B08F40CE7E9E9D413D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_4FE726617ACFEBEF869ECE7E9E9D4BD4" xlink:to="loc_srt_MinimumMember_35C682F7AB8611B08F40CE7E9E9D413D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_4E4A2E162DBDAAE526C0CE7E9E9EA6EE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_4FE726617ACFEBEF869ECE7E9E9D4BD4" xlink:to="loc_srt_MaximumMember_4E4A2E162DBDAAE526C0CE7E9E9EA6EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDepreciationMethods" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentDepreciationMethods_37820326901708E2D6F3CE7E9E9E17E6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentDepreciationMethods_37820326901708E2D6F3CE7E9E9E17E6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives_D93C89B6433EE74A88A5CE7E9E9EFE81" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentEstimatedUsefulLives_D93C89B6433EE74A88A5CE7E9E9EFE81" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_72A4A06A323A607BD7E2CE7E9E9FB73D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_72A4A06A323A607BD7E2CE7E9E9FB73D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_785AF5B7C5EB9AD14227CE7E9E9F6C63" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_785AF5B7C5EB9AD14227CE7E9E9F6C63" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_C30F70615C3F6DCF4A7BCE7E9E9F86FC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_C30F70615C3F6DCF4A7BCE7E9E9F86FC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_952E220A0491321B400FCE7E9E9F42B0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_3E5A4618C741110189A5CE7E9E9EA5E5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_952E220A0491321B400FCE7E9E9F42B0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/PropertyPlantAndEquipmentTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/RestructuringAndImpairmentNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_BD6D650FFE49C980226317FEFD7B2802" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_BD6D650FFE49C980226317FEFD7B2802" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_0D35A4A85FD8F0965D1317FEFD7BAFFA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_BD6D650FFE49C980226317FEFD7B2802" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_0D35A4A85FD8F0965D1317FEFD7BAFFA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_83E9718441775FA4D86117FEFD7BC49C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_0D35A4A85FD8F0965D1317FEFD7BAFFA" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_83E9718441775FA4D86117FEFD7BC49C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_83E9718441775FA4D86117FEFD7BC49C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_0D35A4A85FD8F0965D1317FEFD7BAFFA" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_83E9718441775FA4D86117FEFD7BC49C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="loc_us-gaap_EmployeeSeveranceMember_2162859EFFB722F8855F17FEFD7BD6AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_83E9718441775FA4D86117FEFD7BC49C" xlink:to="loc_us-gaap_EmployeeSeveranceMember_2162859EFFB722F8855F17FEFD7BD6AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherRestructuringMember" xlink:label="loc_us-gaap_OtherRestructuringMember_E20F429E8093D8FE6DF417FEFD7B5B8B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_83E9718441775FA4D86117FEFD7BC49C" xlink:to="loc_us-gaap_OtherRestructuringMember_E20F429E8093D8FE6DF417FEFD7B5B8B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringPlanAxis" xlink:label="loc_us-gaap_RestructuringPlanAxis_A03766F9BD3E71FF909217FEFD7B4AAA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_BD6D650FFE49C980226317FEFD7B2802" xlink:to="loc_us-gaap_RestructuringPlanAxis_A03766F9BD3E71FF909217FEFD7B4AAA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringPlanDomain" xlink:label="loc_us-gaap_RestructuringPlanDomain_4FD920F8AD862BD81EF717FEFD7B793C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringPlanAxis_A03766F9BD3E71FF909217FEFD7B4AAA" xlink:to="loc_us-gaap_RestructuringPlanDomain_4FD920F8AD862BD81EF717FEFD7B793C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringPlanDomain" xlink:label="loc_us-gaap_RestructuringPlanDomain_4FD920F8AD862BD81EF717FEFD7B793C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringPlanAxis_A03766F9BD3E71FF909217FEFD7B4AAA" xlink:to="loc_us-gaap_RestructuringPlanDomain_4FD920F8AD862BD81EF717FEFD7B793C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_IntegrationofEngilityMember" xlink:label="loc_saic_IntegrationofEngilityMember_3A6C8B3A22D4176B74B017FEFD7BEA46" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_4FD920F8AD862BD81EF717FEFD7B793C" xlink:to="loc_saic_IntegrationofEngilityMember_3A6C8B3A22D4176B74B017FEFD7BEA46" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_A2018RestructuringMember" xlink:label="loc_saic_A2018RestructuringMember_706550AD8607A288580F17FEFD7BE650" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_4FD920F8AD862BD81EF717FEFD7B793C" xlink:to="loc_saic_A2018RestructuringMember_706550AD8607A288580F17FEFD7BE650" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_CE612A507A171887917117FEFD7B901A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_BD6D650FFE49C980226317FEFD7B2802" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_CE612A507A171887917117FEFD7B901A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_12E57D4DEECD0E2E585517FEFD7BF183_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_CE612A507A171887917117FEFD7B901A" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_12E57D4DEECD0E2E585517FEFD7BF183_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_12E57D4DEECD0E2E585517FEFD7BF183" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_CE612A507A171887917117FEFD7B901A" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_12E57D4DEECD0E2E585517FEFD7BF183" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfSalesMember" xlink:label="loc_us-gaap_CostOfSalesMember_D5193AA9D3FAD89A0D6217FEFD7B83AD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_12E57D4DEECD0E2E585517FEFD7BF183" xlink:to="loc_us-gaap_CostOfSalesMember_D5193AA9D3FAD89A0D6217FEFD7B83AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_6A9306EFCEC2693DE9E317FEFD7BF485" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_12E57D4DEECD0E2E585517FEFD7BF183" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_6A9306EFCEC2693DE9E317FEFD7BF485" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringAndRelatedCostIncurredCost" xlink:label="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_5A943642A63F7D5FC21517FEFD7B3661" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_RestructuringAndRelatedCostIncurredCost_5A943642A63F7D5FC21517FEFD7B3661" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringCosts" xlink:label="loc_us-gaap_RestructuringCosts_E9A3BC5CD73C4192CB9617FEFD7B4A5D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_RestructuringCosts_E9A3BC5CD73C4192CB9617FEFD7B4A5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringAndRelatedCostExpectedCost1" xlink:label="loc_us-gaap_RestructuringAndRelatedCostExpectedCost1_D9BEB7A15C7C84A2853417FEFD7B788E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_RestructuringAndRelatedCostExpectedCost1_D9BEB7A15C7C84A2853417FEFD7B788E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SeveranceCosts1" xlink:label="loc_us-gaap_SeveranceCosts1_AAACE866B600454A38D017FEFD7BDDF8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_SeveranceCosts1_AAACE866B600454A38D017FEFD7BDDF8" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RestructuringCostsLeaseExitCosts" xlink:label="loc_saic_RestructuringCostsLeaseExitCosts_493EB14DC0DE995FB00F17FEFD7BA4BF" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_saic_RestructuringCostsLeaseExitCosts_493EB14DC0DE995FB00F17FEFD7BA4BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherRestructuringCosts" xlink:label="loc_us-gaap_OtherRestructuringCosts_EE4547713C7B7A61662D17FEFD7B51F7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_OtherRestructuringCosts_EE4547713C7B7A61662D17FEFD7B51F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsForRestructuring" xlink:label="loc_us-gaap_PaymentsForRestructuring_EEEF810C03A5BA6E94BD180AB92C3772" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_PaymentsForRestructuring_EEEF810C03A5BA6E94BD180AB92C3772" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1" xlink:label="loc_us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1_7A41C88EDD5FE5F051F817FEFD7B76A5" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1_7A41C88EDD5FE5F051F817FEFD7B76A5" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_OperatingLeaseRightofUseAssetImpairment" xlink:label="loc_saic_OperatingLeaseRightofUseAssetImpairment_BD0F7F10FED8A3F853E917FEFD7B3C90" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_FBDB8293EC612D2E999D17FEFD7B0793" xlink:to="loc_saic_OperatingLeaseRightofUseAssetImpairment_BD0F7F10FED8A3F853E917FEFD7B3C90" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RestructuringAndImpairmentNotes" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/RestructuringAndImpairmentScheduleOfRestructuringCostsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/RestructuringAndImpairmentTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlans" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansAmountsRecognizedInBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_9B1F4F5C24BDBCF81BC30D10B1B0D2E4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_636C7D4D00350D725FC30D10B1AFF678" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_9B1F4F5C24BDBCF81BC30D10B1B0D2E4" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_636C7D4D00350D725FC30D10B1AFF678" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_CB980BC4C3CE5CEC19CA0D10B1AF0CD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_636C7D4D00350D725FC30D10B1AFF678" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_CB980BC4C3CE5CEC19CA0D10B1AF0CD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_85E0DD44A694B446758F0D10B1AFE516_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_CB980BC4C3CE5CEC19CA0D10B1AF0CD0" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_85E0DD44A694B446758F0D10B1AFE516_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_85E0DD44A694B446758F0D10B1AFE516" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_CB980BC4C3CE5CEC19CA0D10B1AF0CD0" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_85E0DD44A694B446758F0D10B1AFE516" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_12D6862BEAEA0475B74F0D10B1B081AB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_85E0DD44A694B446758F0D10B1AFE516" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_12D6862BEAEA0475B74F0D10B1B081AB" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RetireeHealthReimbursementAccountPlanMember" xlink:label="loc_saic_RetireeHealthReimbursementAccountPlanMember_C22E1D54EA7A47DA1CD90D10B1B03F7E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_85E0DD44A694B446758F0D10B1AFE516" xlink:to="loc_saic_RetireeHealthReimbursementAccountPlanMember_C22E1D54EA7A47DA1CD90D10B1B03F7E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_B2DE48D2C7CE986A8EC70D10B1B15125" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_9B1F4F5C24BDBCF81BC30D10B1B0D2E4" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_B2DE48D2C7CE986A8EC70D10B1B15125" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_2243FED0D39DDA1A22CB0D10B1B1904A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_9B1F4F5C24BDBCF81BC30D10B1B0D2E4" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_2243FED0D39DDA1A22CB0D10B1B1904A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_B5A196C4916C81A6CBD80D10B1B1BA44" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_9B1F4F5C24BDBCF81BC30D10B1B0D2E4" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_B5A196C4916C81A6CBD80D10B1B1BA44" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansAssumptionsUsedDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6D57D13E849B3AC736ED0D10B19F57D6" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_964EABBC4F3AFDFAA25D0D10B19E3ECC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6D57D13E849B3AC736ED0D10B19F57D6" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_964EABBC4F3AFDFAA25D0D10B19E3ECC" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_ECFEF03EE96AB680B2140D10B19E3F7B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_964EABBC4F3AFDFAA25D0D10B19E3ECC" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_ECFEF03EE96AB680B2140D10B19E3F7B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_3A0022AF588692DE19310D10B19FDED6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_ECFEF03EE96AB680B2140D10B19E3F7B" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_3A0022AF588692DE19310D10B19FDED6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_3A0022AF588692DE19310D10B19FDED6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_ECFEF03EE96AB680B2140D10B19E3F7B" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_3A0022AF588692DE19310D10B19FDED6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_E6DCEF02EBD93AD2CC9C0D10B19F7ECA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_3A0022AF588692DE19310D10B19FDED6" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_E6DCEF02EBD93AD2CC9C0D10B19F7ECA" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RetireeHealthReimbursementAccountPlanMember" xlink:label="loc_saic_RetireeHealthReimbursementAccountPlanMember_D30492338A46DA06D6CB0D10B19F272E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_3A0022AF588692DE19310D10B19FDED6" xlink:to="loc_saic_RetireeHealthReimbursementAccountPlanMember_D30492338A46DA06D6CB0D10B19F272E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_A0D6B4B9AAB723375F110D10B1A5EA69" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6D57D13E849B3AC736ED0D10B19F57D6" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_A0D6B4B9AAB723375F110D10B1A5EA69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate_C7B325145BC54CEF8DB80D6093DAD915" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6D57D13E849B3AC736ED0D10B19F57D6" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate_C7B325145BC54CEF8DB80D6093DAD915" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_0B027879A6F8B4DD01E80D61700D2BC4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6D57D13E849B3AC736ED0D10B19F57D6" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_0B027879A6F8B4DD01E80D61700D2BC4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansEstimatedFutureBenefitPaymentDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_0A92E7C2286A37BA7A761759CCB862D3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_0A92E7C2286A37BA7A761759CCB862D3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_C495811E30B3CF1033F01759CCB9625F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_0A92E7C2286A37BA7A761759CCB862D3" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_C495811E30B3CF1033F01759CCB9625F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_5C8758101844555CA7241759CCB93EE5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_C495811E30B3CF1033F01759CCB9625F" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_5C8758101844555CA7241759CCB93EE5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_5C8758101844555CA7241759CCB93EE5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_C495811E30B3CF1033F01759CCB9625F" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_5C8758101844555CA7241759CCB93EE5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_0E025D8DFD39ACFD8B1D1759CCB9552A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_5C8758101844555CA7241759CCB93EE5" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_0E025D8DFD39ACFD8B1D1759CCB9552A" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RetireeHealthReimbursementAccountPlanMember" xlink:label="loc_saic_RetireeHealthReimbursementAccountPlanMember_7DD9991469F0F3C281151759CCBA0074" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_5C8758101844555CA7241759CCB93EE5" xlink:to="loc_saic_RetireeHealthReimbursementAccountPlanMember_7DD9991469F0F3C281151759CCBA0074" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_260392A0DC031A75F6C61759CCBA5643" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_260392A0DC031A75F6C61759CCBA5643" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_34768046393A0AB6278E1759CCBAC83E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_34768046393A0AB6278E1759CCBAC83E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_8F36013C11F9CC2761901759CCBA0846" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_8F36013C11F9CC2761901759CCBA0846" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_1C2D795557F6F9AAFE1B1759CCBBD699" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_1C2D795557F6F9AAFE1B1759CCBBD699" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_CD0C058045A18181863B1759CCBB8342" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_CD0C058045A18181863B1759CCBB8342" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_12144AE0EFC0F4F2CA681759CCBB592D" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_F960DB3AA9A9AD6C38241759CCBA3A01" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_12144AE0EFC0F4F2CA681759CCBB592D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansFairValueMeasurementPlanAssetsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_A1D7C392BCA76B1A79640D10B199E89C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_33517CF3DE318010CA840D10B191752B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_A1D7C392BCA76B1A79640D10B199E89C" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_33517CF3DE318010CA840D10B191752B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_1066287F3D4EADD31BD50D10B192ADC1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_33517CF3DE318010CA840D10B191752B" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_1066287F3D4EADD31BD50D10B192ADC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_1066287F3D4EADD31BD50D10B192ADC1" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_1066287F3D4EADD31BD50D10B192ADC1" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityFundsMember" xlink:label="loc_us-gaap_EquityFundsMember_ED2B531D471AD22842E90D65CA354C46" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2" xlink:to="loc_us-gaap_EquityFundsMember_ED2B531D471AD22842E90D65CA354C46" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FixedIncomeFundsMember" xlink:label="loc_us-gaap_FixedIncomeFundsMember_D754E03E01F997614E1F0D65CA647E84" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2" xlink:to="loc_us-gaap_FixedIncomeFundsMember_D754E03E01F997614E1F0D65CA647E84" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_GuaranteedDepositAccountMember" xlink:label="loc_saic_GuaranteedDepositAccountMember_865B273BC464BD0958580D10B193A48A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2" xlink:to="loc_saic_GuaranteedDepositAccountMember_865B273BC464BD0958580D10B193A48A" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DefinedBenefitPlanMutualFundandGuaranteedDepositAccountMember" xlink:label="loc_saic_DefinedBenefitPlanMutualFundandGuaranteedDepositAccountMember_7EE93ED374BF11881AE10D709143E8A9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2" xlink:to="loc_saic_DefinedBenefitPlanMutualFundandGuaranteedDepositAccountMember_7EE93ED374BF11881AE10D709143E8A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember" xlink:label="loc_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember_3B67F8114B7704D6AA390D6EF73B1B78" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_DECB64214735642993550D10B19202E2" xlink:to="loc_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember_3B67F8114B7704D6AA390D6EF73B1B78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7D599A0E68039C4ECDCB0D10B193A41D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_33517CF3DE318010CA840D10B191752B" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7D599A0E68039C4ECDCB0D10B193A41D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_CA7D3437EF08217333BC0D10B193F01C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7D599A0E68039C4ECDCB0D10B193A41D" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_CA7D3437EF08217333BC0D10B193F01C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_CA7D3437EF08217333BC0D10B193F01C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_7D599A0E68039C4ECDCB0D10B193A41D" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_CA7D3437EF08217333BC0D10B193F01C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_3C2612B64B5293BB5CA60D10B1931062" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_CA7D3437EF08217333BC0D10B193F01C" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_3C2612B64B5293BB5CA60D10B1931062" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_F31A471237AF515D4D530D10B194F1B7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_CA7D3437EF08217333BC0D10B193F01C" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_F31A471237AF515D4D530D10B194F1B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember" xlink:label="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_B7F10B0065204633C1ED0D6D7FDCCFEA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_CA7D3437EF08217333BC0D10B193F01C" xlink:to="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_B7F10B0065204633C1ED0D6D7FDCCFEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_C6A028108B9DBFDC99D30D10B19986D4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_A1D7C392BCA76B1A79640D10B199E89C" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_C6A028108B9DBFDC99D30D10B19986D4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_71B07678AF27500B8B3F0DC1C0A533E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_71B07678AF27500B8B3F0DC1C0A533E2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_DF60523EF66B50CB5EBA0DC1C0A66567" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_71B07678AF27500B8B3F0DC1C0A533E2" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_DF60523EF66B50CB5EBA0DC1C0A66567" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_DF60523EF66B50CB5EBA0DC1C0A66567" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_DF60523EF66B50CB5EBA0DC1C0A66567" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_6AD2CD2B5D51B985B2C90DC1C0A66B26" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_6AD2CD2B5D51B985B2C90DC1C0A66B26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_A1F80C20EB56F17BA3650DC1C0A68CDE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_A1F80C20EB56F17BA3650DC1C0A68CDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FixedIncomeSecuritiesMember" xlink:label="loc_us-gaap_FixedIncomeSecuritiesMember_454BEC75981575C81E320DC1C0A635C9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435" xlink:to="loc_us-gaap_FixedIncomeSecuritiesMember_454BEC75981575C81E320DC1C0A635C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember_3D2F02B8854459BA65160DC1C0A7C345" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_2D65B7A0285E49D7854E0DC1C0A6B435" xlink:to="loc_us-gaap_DefinedBenefitPlanCashAndCashEquivalentsMember_3D2F02B8854459BA65160DC1C0A7C345" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_00F60C2A5EEDF34935AA0DC1C0A7DD42" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_71B07678AF27500B8B3F0DC1C0A533E2" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_00F60C2A5EEDF34935AA0DC1C0A7DD42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_64D8651945502821DD0C0DC1C0A70602_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_00F60C2A5EEDF34935AA0DC1C0A7DD42" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_64D8651945502821DD0C0DC1C0A70602_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_64D8651945502821DD0C0DC1C0A70602" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_00F60C2A5EEDF34935AA0DC1C0A7DD42" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_64D8651945502821DD0C0DC1C0A70602" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_0D2E19A5A201E75F110F0DC1C0A7DA4B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_64D8651945502821DD0C0DC1C0A70602" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_0D2E19A5A201E75F110F0DC1C0A7DA4B" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RetireeHealthReimbursementAccountPlanMember" xlink:label="loc_saic_RetireeHealthReimbursementAccountPlanMember_88D6C2194F8AA089012D0DC646EE54A3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_64D8651945502821DD0C0DC1C0A70602" xlink:to="loc_saic_RetireeHealthReimbursementAccountPlanMember_88D6C2194F8AA089012D0DC646EE54A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedContributionPlanCostRecognized" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_AFEC39F5B11FC05F5B850DC1C0A8A506" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_AFEC39F5B11FC05F5B850DC1C0A8A506" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_09218BD137A5CE2F06D20DC5489F3129" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_09218BD137A5CE2F06D20DC5489F3129" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_DE456376B978E67105600DC1C0A82038" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_DE456376B978E67105600DC1C0A82038" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_976DE87B4C0F2FA70A010DC1C0A8E45C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_976DE87B4C0F2FA70A010DC1C0A8E45C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_E2C83560B86E8750E7CD0DC1C0A88A46" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_E2C83560B86E8750E7CD0DC1C0A88A46" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_B79B89E860D6EC5BF2D50DCB390A4185" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_B79B89E860D6EC5BF2D50DCB390A4185" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DefinedBenefitPlanBenefitObligationIncreaseDecreaseForDiscountRateChange" xlink:label="loc_saic_DefinedBenefitPlanBenefitObligationIncreaseDecreaseForDiscountRateChange_C649D5C624235E12D1CF0DD2F64F36B3" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_saic_DefinedBenefitPlanBenefitObligationIncreaseDecreaseForDiscountRateChange_C649D5C624235E12D1CF0DD2F64F36B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_15423A270A42AA738FDD0DCFE5DA8090" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_15423A270A42AA738FDD0DCFE5DA8090" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DefinedBenefitPlanPlanAssetsLongtermRateofReturn" xlink:label="loc_saic_DefinedBenefitPlanPlanAssetsLongtermRateofReturn_EBF942A7E29CAFFB0B150DC1C0A9ECE8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_saic_DefinedBenefitPlanPlanAssetsLongtermRateofReturn_EBF942A7E29CAFFB0B150DC1C0A9ECE8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_A4CE2A48F1FE5D3494C20DC1C0A90B0B" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_C2EBE5AFCB95723585700DC1C0A8A27C" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_A4CE2A48F1FE5D3494C20DC1C0A90B0B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansNetPeriodicBenefitIncomeExpenseDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_292610E624CCA42EC4230D10B17AEBD3" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_AFD6DDD85C426EE4A3820D10B17992A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_292610E624CCA42EC4230D10B17AEBD3" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_AFD6DDD85C426EE4A3820D10B17992A7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_7799286498E8FF196CC70D10B179A016" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_AFD6DDD85C426EE4A3820D10B17992A7" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_7799286498E8FF196CC70D10B179A016" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_FE6E19FA6F9BB32CBCF00D10B179E27A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_7799286498E8FF196CC70D10B179A016" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_FE6E19FA6F9BB32CBCF00D10B179E27A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_FE6E19FA6F9BB32CBCF00D10B179E27A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_7799286498E8FF196CC70D10B179A016" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_FE6E19FA6F9BB32CBCF00D10B179E27A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_1319887E79DEBC6E17650D10B17A0083" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_FE6E19FA6F9BB32CBCF00D10B179E27A" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_1319887E79DEBC6E17650D10B17A0083" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RetireeHealthReimbursementAccountPlanMember" xlink:label="loc_saic_RetireeHealthReimbursementAccountPlanMember_1EFA639E03EE1A5400190D10B17A490F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_FE6E19FA6F9BB32CBCF00D10B179E27A" xlink:to="loc_saic_RetireeHealthReimbursementAccountPlanMember_1EFA639E03EE1A5400190D10B17A490F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_88A6594ACBDC6AFF04D00D10B17A1815" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_292610E624CCA42EC4230D10B17AEBD3" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_88A6594ACBDC6AFF04D00D10B17A1815" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_9A352ADC3E9A95C7486B0D10B17B1332" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_292610E624CCA42EC4230D10B17AEBD3" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_9A352ADC3E9A95C7486B0D10B17B1332" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_5941497DB300EBF99D1A0D10B17B831D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_292610E624CCA42EC4230D10B17AEBD3" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_5941497DB300EBF99D1A0D10B17B831D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansObligationsAndFundedStatusDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_CE3667205A4C11FE85B40D10B1BE2C60" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_F5B5D473B828FCDF720F0D10B1BDD7EA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_CE3667205A4C11FE85B40D10B1BE2C60" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_F5B5D473B828FCDF720F0D10B1BDD7EA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeAxis" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_6351F3B6B880A9A7862F0D10B1BD3397" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_F5B5D473B828FCDF720F0D10B1BDD7EA" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_6351F3B6B880A9A7862F0D10B1BD3397" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_2247C4D0BD096E7069FD0D10B1BD7022_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_6351F3B6B880A9A7862F0D10B1BD3397" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_2247C4D0BD096E7069FD0D10B1BD7022_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetirementPlanTypeDomain" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_2247C4D0BD096E7069FD0D10B1BD7022" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_6351F3B6B880A9A7862F0D10B1BD3397" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_2247C4D0BD096E7069FD0D10B1BD7022" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_CA24B4A6051D345D75D10D10B1BED847" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_2247C4D0BD096E7069FD0D10B1BD7022" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_CA24B4A6051D345D75D10D10B1BED847" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_RetireeHealthReimbursementAccountPlanMember" xlink:label="loc_saic_RetireeHealthReimbursementAccountPlanMember_2A437EF61DE7B9ADE69F0D10B1BE1229" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_2247C4D0BD096E7069FD0D10B1BD7022" xlink:to="loc_saic_RetireeHealthReimbursementAccountPlanMember_2A437EF61DE7B9ADE69F0D10B1BE1229" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_19669C92309FF929E0F30D10B1BFC76E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_CE3667205A4C11FE85B40D10B1BE2C60" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_19669C92309FF929E0F30D10B1BFC76E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligation" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_2D394FDEDAC8B1E6B3FD0D10B1BF5432" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_19669C92309FF929E0F30D10B1BFC76E" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_2D394FDEDAC8B1E6B3FD0D10B1BF5432" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_6C67689921622F9493300D10B1BE4826" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_19669C92309FF929E0F30D10B1BFC76E" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_6C67689921622F9493300D10B1BE4826" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_2A59D6DAF86738B27BF80D2C3C084270" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_19669C92309FF929E0F30D10B1BFC76E" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_2A59D6DAF86738B27BF80D2C3C084270" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_F1A07E84A6FF486FA1930D2C3C335106" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_19669C92309FF929E0F30D10B1BFC76E" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_F1A07E84A6FF486FA1930D2C3C335106" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_B93689ABA31ED77B6EF20D10B1BFA1C9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_CE3667205A4C11FE85B40D10B1BE2C60" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_B93689ABA31ED77B6EF20D10B1BFA1C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_403C114A28BFAA141C590D10B1C0351A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_B93689ABA31ED77B6EF20D10B1BFA1C9" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_403C114A28BFAA141C590D10B1C0351A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_1E5084B036FD77D9F4B10D2D1ECE40C9" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_B93689ABA31ED77B6EF20D10B1BFA1C9" xlink:to="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_1E5084B036FD77D9F4B10D2D1ECE40C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_0485774CF4684BDC9F8A0D10B1C0A730" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_B93689ABA31ED77B6EF20D10B1BFA1C9" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_0485774CF4684BDC9F8A0D10B1C0A730" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_DB694FD74B79BD7ED8A80D2D1F0D5698" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_B93689ABA31ED77B6EF20D10B1BFA1C9" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_DB694FD74B79BD7ED8A80D2D1F0D5698" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_757D3341DA7DB04C460D0D10B1C0D444" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_CE3667205A4C11FE85B40D10B1BE2C60" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_757D3341DA7DB04C460D0D10B1C0D444" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansScheduleOfGuaranteedDepositAccountsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_13458E27D8854BAFED640DC1C0469FD7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_E80DA907CAF8B3886A3D0DC1C0448BC4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_13458E27D8854BAFED640DC1C0469FD7" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_E80DA907CAF8B3886A3D0DC1C0448BC4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_08B42FC9A168E89F23F60DC1C0457E54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_E80DA907CAF8B3886A3D0DC1C0448BC4" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_08B42FC9A168E89F23F60DC1C0457E54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_399B85F45FF26E54FD880DC1C04565B9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_08B42FC9A168E89F23F60DC1C0457E54" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_399B85F45FF26E54FD880DC1C04565B9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanAssetCategoriesDomain" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_399B85F45FF26E54FD880DC1C04565B9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_08B42FC9A168E89F23F60DC1C0457E54" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_399B85F45FF26E54FD880DC1C04565B9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_FE7BE5899F56189C1F280DC1C0454581" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_E80DA907CAF8B3886A3D0DC1C0448BC4" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_FE7BE5899F56189C1F280DC1C0454581" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ACAF63414BABB9EE4DE0DC1C0453BA6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_FE7BE5899F56189C1F280DC1C0454581" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ACAF63414BABB9EE4DE0DC1C0453BA6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ACAF63414BABB9EE4DE0DC1C0453BA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_FE7BE5899F56189C1F280DC1C0454581" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ACAF63414BABB9EE4DE0DC1C0453BA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_D49AEA9AD6D997C438BE0DC1C046E284" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_4ACAF63414BABB9EE4DE0DC1C0453BA6" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_D49AEA9AD6D997C438BE0DC1C046E284" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_E0EF993340EF8AD959E10DC1C046548F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_13458E27D8854BAFED640DC1C0469FD7" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_E0EF993340EF8AD959E10DC1C046548F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_GuaranteedDepositAccountsAmount" xlink:label="loc_saic_GuaranteedDepositAccountsAmount_DBE41FB0E11F3420F90C0DC1C04689EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_E0EF993340EF8AD959E10DC1C046548F" xlink:to="loc_saic_GuaranteedDepositAccountsAmount_DBE41FB0E11F3420F90C0DC1C04689EC" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_GuaranteedDepositAccountIncreaseForPurchases" xlink:label="loc_saic_GuaranteedDepositAccountIncreaseForPurchases_48208000005DB564E6BC0DC1C047FC65" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_E0EF993340EF8AD959E10DC1C046548F" xlink:to="loc_saic_GuaranteedDepositAccountIncreaseForPurchases_48208000005DB564E6BC0DC1C047FC65" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_GuaranteedDepositAccountDecreaseFromSales" xlink:label="loc_saic_GuaranteedDepositAccountDecreaseFromSales_5DB46BD9AD0543BCFF0D0DC1C04C8011" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_E0EF993340EF8AD959E10DC1C046548F" xlink:to="loc_saic_GuaranteedDepositAccountDecreaseFromSales_5DB46BD9AD0543BCFF0D0DC1C04C8011" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RetirementPlansTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/Revenues" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/RevenuesChangeInEstimatesOnContractsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/RevenuesContractBalancesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_399309FF264595044C603FD68CB70F5F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_F1E1F838E866E4D4AF7F3FD68CB6B323" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_399309FF264595044C603FD68CB70F5F" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_F1E1F838E866E4D4AF7F3FD68CB6B323" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_4E69954FD41982147BF63FD68CB6ADC7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_F1E1F838E866E4D4AF7F3FD68CB6B323" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_4E69954FD41982147BF63FD68CB6ADC7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_4E69954FD41982147BF63FD68CB6ADC7" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_4E69954FD41982147BF63FD68CB6ADC7" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TradeAccountsReceivableMember" xlink:label="loc_us-gaap_TradeAccountsReceivableMember_CCDE2081297A7DDD7C263FD68CB75B14" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792" xlink:to="loc_us-gaap_TradeAccountsReceivableMember_CCDE2081297A7DDD7C263FD68CB75B14" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_06C708DF9321F61A2FFD3FD68CB7AC1F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792" xlink:to="loc_us-gaap_OtherAssetsMember_06C708DF9321F61A2FFD3FD68CB7AC1F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_OtherAccruedLIabilitiesMember" xlink:label="loc_saic_OtherAccruedLIabilitiesMember_1B56E0D7B17BCE1BC10D3FD68CB7CEFB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792" xlink:to="loc_saic_OtherAccruedLIabilitiesMember_1B56E0D7B17BCE1BC10D3FD68CB7CEFB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_18BE2CB7DE854FC933C63FD68CB704BC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_21A656006EA304C370053FD68CB67792" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_18BE2CB7DE854FC933C63FD68CB704BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BilledContractReceivables" xlink:label="loc_us-gaap_BilledContractReceivables_37D86D5F904013B12E553FD68CB80BEA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_399309FF264595044C603FD68CB70F5F" xlink:to="loc_us-gaap_BilledContractReceivables_37D86D5F904013B12E553FD68CB80BEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerAssetNet" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_C94F33FE306D393361133FD68CB89778" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_399309FF264595044C603FD68CB70F5F" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_C94F33FE306D393361133FD68CB89778" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_CB1122E091182223B44E3FD68CB83DD1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_399309FF264595044C603FD68CB70F5F" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_CB1122E091182223B44E3FD68CB83DD1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_E5A979F284329C1E1E063FD68CB8521A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_399309FF264595044C603FD68CB70F5F" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_E5A979F284329C1E1E063FD68CB8521A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RevenuesDeferredCostsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostLineItems" xlink:label="loc_us-gaap_CapitalizedContractCostLineItems_61B9A1F0D60CF0E45E97B0151CF3BFFF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostTable" xlink:label="loc_us-gaap_CapitalizedContractCostTable_018C040836DB47EB8BE7B0151CF360CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_61B9A1F0D60CF0E45E97B0151CF3BFFF" xlink:to="loc_us-gaap_CapitalizedContractCostTable_018C040836DB47EB8BE7B0151CF360CE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_64755D998E27ADF6B7B0B0151CF35D2E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_018C040836DB47EB8BE7B0151CF360CE" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_64755D998E27ADF6B7B0B0151CF35D2E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_F09ECB19C62444ABE197B0151CF3A68A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_64755D998E27ADF6B7B0B0151CF35D2E" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_F09ECB19C62444ABE197B0151CF3A68A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_F09ECB19C62444ABE197B0151CF3A68A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_64755D998E27ADF6B7B0B0151CF35D2E" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_F09ECB19C62444ABE197B0151CF3A68A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherCurrentAssetsMember" xlink:label="loc_us-gaap_OtherCurrentAssetsMember_D459BA2C9DA524BBCE70B0151CF30A54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_F09ECB19C62444ABE197B0151CF3A68A" xlink:to="loc_us-gaap_OtherCurrentAssetsMember_D459BA2C9DA524BBCE70B0151CF30A54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAssetsMember" xlink:label="loc_us-gaap_OtherAssetsMember_2E4CF8229F8348148C05B0151CF3CC2D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_F09ECB19C62444ABE197B0151CF3A68A" xlink:to="loc_us-gaap_OtherAssetsMember_2E4CF8229F8348148C05B0151CF3CC2D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostAxis" xlink:label="loc_us-gaap_CapitalizedContractCostAxis_FF4BFF850335C65E9EE6B0151CF3FF1F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_018C040836DB47EB8BE7B0151CF360CE" xlink:to="loc_us-gaap_CapitalizedContractCostAxis_FF4BFF850335C65E9EE6B0151CF3FF1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostDomain" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_06800A8C8898DB5D6316B0151CF39049_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_FF4BFF850335C65E9EE6B0151CF3FF1F" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_06800A8C8898DB5D6316B0151CF39049_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostDomain" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_06800A8C8898DB5D6316B0151CF39049" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_FF4BFF850335C65E9EE6B0151CF3FF1F" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_06800A8C8898DB5D6316B0151CF39049" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PreContractCostMember" xlink:label="loc_saic_PreContractCostMember_B4A3D3E1D6340EB96BA4B0151CF3C186" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_06800A8C8898DB5D6316B0151CF39049" xlink:to="loc_saic_PreContractCostMember_B4A3D3E1D6340EB96BA4B0151CF3C186" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_FulfillmentCostCurrentMember" xlink:label="loc_saic_FulfillmentCostCurrentMember_489F82A58AA4A6173D3CB0151CF3B7F2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_06800A8C8898DB5D6316B0151CF39049" xlink:to="loc_saic_FulfillmentCostCurrentMember_489F82A58AA4A6173D3CB0151CF3B7F2" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_FulfillmentCostNonCurrentMember" xlink:label="loc_saic_FulfillmentCostNonCurrentMember_5FAC8A68EE53E56BF4F6B0151CF3DF21" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_06800A8C8898DB5D6316B0151CF39049" xlink:to="loc_saic_FulfillmentCostNonCurrentMember_5FAC8A68EE53E56BF4F6B0151CF3DF21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostNet" xlink:label="loc_us-gaap_CapitalizedContractCostNet_CF89AE2803731A230606B0151CF34ED4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_61B9A1F0D60CF0E45E97B0151CF3BFFF" xlink:to="loc_us-gaap_CapitalizedContractCostNet_CF89AE2803731A230606B0151CF34ED4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RevenuesDisaggregationOfRevenuesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_0B56CDF6B555CC6D1D17B496CEA80E8F" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_493C22119AE90F62FCB9B496CEA4D120" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_0B56CDF6B555CC6D1D17B496CEA80E8F" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_493C22119AE90F62FCB9B496CEA4D120" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MajorCustomersAxis" xlink:label="loc_srt_MajorCustomersAxis_98CBC6A247F6FA94D7C5B496CEA4686A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_493C22119AE90F62FCB9B496CEA4D120" xlink:to="loc_srt_MajorCustomersAxis_98CBC6A247F6FA94D7C5B496CEA4686A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_C504370FB1FFC94B4416B496CEA42B6B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_98CBC6A247F6FA94D7C5B496CEA4686A" xlink:to="loc_srt_NameOfMajorCustomerDomain_C504370FB1FFC94B4416B496CEA42B6B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="loc_srt_NameOfMajorCustomerDomain_C504370FB1FFC94B4416B496CEA42B6B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_98CBC6A247F6FA94D7C5B496CEA4686A" xlink:to="loc_srt_NameOfMajorCustomerDomain_C504370FB1FFC94B4416B496CEA42B6B" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_DepartmentOfDefenseMember" xlink:label="loc_saic_DepartmentOfDefenseMember_C2E84C7CAF7A7738DBF4B496CEA54F83" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_C504370FB1FFC94B4416B496CEA42B6B" xlink:to="loc_saic_DepartmentOfDefenseMember_C2E84C7CAF7A7738DBF4B496CEA54F83" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_OtherFederalGovernmentAgenciesMember" xlink:label="loc_saic_OtherFederalGovernmentAgenciesMember_FEF166F75A5CE94F4615B496CEA550EE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_C504370FB1FFC94B4416B496CEA42B6B" xlink:to="loc_saic_OtherFederalGovernmentAgenciesMember_FEF166F75A5CE94F4615B496CEA550EE" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_CommercialStateAndLocalAgenciesMember" xlink:label="loc_saic_CommercialStateAndLocalAgenciesMember_84466FBAFA0B4E90DEF3B496CEA559F5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_C504370FB1FFC94B4416B496CEA42B6B" xlink:to="loc_saic_CommercialStateAndLocalAgenciesMember_84466FBAFA0B4E90DEF3B496CEA559F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingAxis" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_EA6B4A9BB88067D6C32EB496CEA5ED4A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_493C22119AE90F62FCB9B496CEA4D120" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_EA6B4A9BB88067D6C32EB496CEA5ED4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_C75A6D40116B18F301DAB496CEA69A34_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_EA6B4A9BB88067D6C32EB496CEA5ED4A" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_C75A6D40116B18F301DAB496CEA69A34_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_C75A6D40116B18F301DAB496CEA69A34" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_EA6B4A9BB88067D6C32EB496CEA5ED4A" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_C75A6D40116B18F301DAB496CEA69A34" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_CostReimbursementContractMember" xlink:label="loc_saic_CostReimbursementContractMember_FA878B52EC302C43DF89B496CEA66D35" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_C75A6D40116B18F301DAB496CEA69A34" xlink:to="loc_saic_CostReimbursementContractMember_FA878B52EC302C43DF89B496CEA66D35" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TimeAndMaterialsContractMember" xlink:label="loc_us-gaap_TimeAndMaterialsContractMember_10ABD736B01BE7C166DDB496CEA7D19A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_C75A6D40116B18F301DAB496CEA69A34" xlink:to="loc_us-gaap_TimeAndMaterialsContractMember_10ABD736B01BE7C166DDB496CEA7D19A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FixedPriceContractMember" xlink:label="loc_us-gaap_FixedPriceContractMember_6D5629FD39C3E124CE1FB496CEA7EFA6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_C75A6D40116B18F301DAB496CEA69A34" xlink:to="loc_us-gaap_FixedPriceContractMember_6D5629FD39C3E124CE1FB496CEA7EFA6" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ContractorAxis" xlink:label="loc_saic_ContractorAxis_48C28D89E5F2B524DE6BB496CEA77C66" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_493C22119AE90F62FCB9B496CEA4D120" xlink:to="loc_saic_ContractorAxis_48C28D89E5F2B524DE6BB496CEA77C66" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ContractorDomain" xlink:label="loc_saic_ContractorDomain_32419568800E587863ADB496CEA75D22_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_saic_ContractorAxis_48C28D89E5F2B524DE6BB496CEA77C66" xlink:to="loc_saic_ContractorDomain_32419568800E587863ADB496CEA75D22_default" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ContractorDomain" xlink:label="loc_saic_ContractorDomain_32419568800E587863ADB496CEA75D22" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_saic_ContractorAxis_48C28D89E5F2B524DE6BB496CEA77C66" xlink:to="loc_saic_ContractorDomain_32419568800E587863ADB496CEA75D22" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PrimeContractorMember" xlink:label="loc_saic_PrimeContractorMember_2D8A663DEA0A878A85BEB496CEA8CC0C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ContractorDomain_32419568800E587863ADB496CEA75D22" xlink:to="loc_saic_PrimeContractorMember_2D8A663DEA0A878A85BEB496CEA8CC0C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SubcontractorMember" xlink:label="loc_saic_SubcontractorMember_03BA92A9A81178885698B496CEA8B247" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ContractorDomain_32419568800E587863ADB496CEA75D22" xlink:to="loc_saic_SubcontractorMember_03BA92A9A81178885698B496CEA8B247" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_OtherContractorMember" xlink:label="loc_saic_OtherContractorMember_5302FA3B372F6D7E63B3B496CEA82941" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_ContractorDomain_32419568800E587863ADB496CEA75D22" xlink:to="loc_saic_OtherContractorMember_5302FA3B372F6D7E63B3B496CEA82941" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B5EAB56A1F252DD512DEB496CEA9A3D5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_0B56CDF6B555CC6D1D17B496CEA80E8F" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_B5EAB56A1F252DD512DEB496CEA9A3D5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RevenuesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_18E8DFB4DE32771B9C2C07C70B823E5C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_AEB4C8B76E23B0C819BC07C70B80302A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_18E8DFB4DE32771B9C2C07C70B823E5C" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_AEB4C8B76E23B0C819BC07C70B80302A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostAxis" xlink:label="loc_us-gaap_CapitalizedContractCostAxis_3FA014DD2A9EAE74384407C70B810747" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_AEB4C8B76E23B0C819BC07C70B80302A" xlink:to="loc_us-gaap_CapitalizedContractCostAxis_3FA014DD2A9EAE74384407C70B810747" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostDomain" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_E6EE73535E0E2498E3FD07C70B81FE0A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_3FA014DD2A9EAE74384407C70B810747" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_E6EE73535E0E2498E3FD07C70B81FE0A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostDomain" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_E6EE73535E0E2498E3FD07C70B81FE0A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_3FA014DD2A9EAE74384407C70B810747" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_E6EE73535E0E2498E3FD07C70B81FE0A" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PreContractCostMember" xlink:label="loc_saic_PreContractCostMember_E2838AA874A5F9A1D31707C70B8166D3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_E6EE73535E0E2498E3FD07C70B81FE0A" xlink:to="loc_saic_PreContractCostMember_E2838AA874A5F9A1D31707C70B8166D3" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PreContractCostNotAwardedMember" xlink:label="loc_saic_PreContractCostNotAwardedMember_AC3A67C6A4786897D33907C70B82163B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_PreContractCostMember_E2838AA874A5F9A1D31707C70B8166D3" xlink:to="loc_saic_PreContractCostNotAwardedMember_AC3A67C6A4786897D33907C70B82163B" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_FulfillmentCostCurrentMember" xlink:label="loc_saic_FulfillmentCostCurrentMember_4417BB2C1EE83A0BB26007C70B82A4EC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_E6EE73535E0E2498E3FD07C70B81FE0A" xlink:to="loc_saic_FulfillmentCostCurrentMember_4417BB2C1EE83A0BB26007C70B82A4EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod" xlink:label="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_C332EB1AC6D74530B86C07C70B824F1F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_18E8DFB4DE32771B9C2C07C70B823E5C" xlink:to="loc_us-gaap_ContractWithCustomerPerformanceObligationSatisfiedInPreviousPeriod_C332EB1AC6D74530B86C07C70B824F1F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_FEBCD783DD371FF1B13407C70B83F139" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_18E8DFB4DE32771B9C2C07C70B823E5C" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_FEBCD783DD371FF1B13407C70B83F139" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CapitalizedContractCostAmortization" xlink:label="loc_us-gaap_CapitalizedContractCostAmortization_41003E6BCBF5822CE2FF07C70B8394EC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_18E8DFB4DE32771B9C2C07C70B823E5C" xlink:to="loc_us-gaap_CapitalizedContractCostAmortization_41003E6BCBF5822CE2FF07C70B8394EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_177E13CA6AA4D2E827A307C70B83AA3B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_18E8DFB4DE32771B9C2C07C70B823E5C" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_177E13CA6AA4D2E827A307C70B83AA3B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RevenuesPerformanceObligationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B6116EFACA8DA9560B9DB01519B7116E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_008FE59CBBAEE6098B4AB01519B72CAF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B6116EFACA8DA9560B9DB01519B7116E" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_008FE59CBBAEE6098B4AB01519B72CAF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PerformancePeriodAxis" xlink:label="loc_saic_PerformancePeriodAxis_497F405516B2FCFAC8E8B01519B7B431" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_008FE59CBBAEE6098B4AB01519B72CAF" xlink:to="loc_saic_PerformancePeriodAxis_497F405516B2FCFAC8E8B01519B7B431" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PerformancePeriodDomain" xlink:label="loc_saic_PerformancePeriodDomain_C24F12B7E4CE185C99B9B01519B7165E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_saic_PerformancePeriodAxis_497F405516B2FCFAC8E8B01519B7B431" xlink:to="loc_saic_PerformancePeriodDomain_C24F12B7E4CE185C99B9B01519B7165E_default" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PerformancePeriodDomain" xlink:label="loc_saic_PerformancePeriodDomain_C24F12B7E4CE185C99B9B01519B7165E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_saic_PerformancePeriodAxis_497F405516B2FCFAC8E8B01519B7B431" xlink:to="loc_saic_PerformancePeriodDomain_C24F12B7E4CE185C99B9B01519B7165E" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_NextTwelveMonthsMember" xlink:label="loc_saic_NextTwelveMonthsMember_885A8D8E5730CCD0B044B01519B7901F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_PerformancePeriodDomain_C24F12B7E4CE185C99B9B01519B7165E" xlink:to="loc_saic_NextTwelveMonthsMember_885A8D8E5730CCD0B044B01519B7901F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_NextTwentyFourMonthsMember" xlink:label="loc_saic_NextTwentyFourMonthsMember_E85B76D122981E3623FCB01519B7B2FB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_saic_PerformancePeriodDomain_C24F12B7E4CE185C99B9B01519B7165E" xlink:to="loc_saic_NextTwentyFourMonthsMember_E85B76D122981E3623FCB01519B7B2FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_EC6F2F7407B85D486213B01519B7FBEB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_008FE59CBBAEE6098B4AB01519B72CAF" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_EC6F2F7407B85D486213B01519B7FBEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_3A44F6F0C21DF40C108FB01519B7E06B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B6116EFACA8DA9560B9DB01519B7116E" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_3A44F6F0C21DF40C108FB01519B7E06B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_11C45976AE2C64AB0943B01519B71DBF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_B6116EFACA8DA9560B9DB01519B7116E" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_11C45976AE2C64AB0943B01519B71DBF" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/RevenuesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/SelectedQuarterlyFinancialDataUnaudited" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/SelectedQuarterlyFinancialDataUnauditedDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/SelectedQuarterlyFinancialDataUnauditedTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationFairValueAndValuationAssumptionsOfStockOptionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2CC453A5F144A03D25B2EE1D7F6D7170" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2CC453A5F144A03D25B2EE1D7F6D7170" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_7AFF8A9F0FE9E990BFE0EE1D7F6D4404" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2CC453A5F144A03D25B2EE1D7F6D7170" xlink:to="loc_us-gaap_AwardTypeAxis_7AFF8A9F0FE9E990BFE0EE1D7F6D4404" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE18458B27D8E6E74CEBEE1D7F6E8DF8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_7AFF8A9F0FE9E990BFE0EE1D7F6D4404" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE18458B27D8E6E74CEBEE1D7F6E8DF8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE18458B27D8E6E74CEBEE1D7F6E8DF8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_7AFF8A9F0FE9E990BFE0EE1D7F6D4404" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE18458B27D8E6E74CEBEE1D7F6E8DF8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_9639E9CB4A00D35E5711EE1D7F6EB186" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE18458B27D8E6E74CEBEE1D7F6E8DF8" xlink:to="loc_us-gaap_EmployeeStockOptionMember_9639E9CB4A00D35E5711EE1D7F6EB186" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_D913C93F89FB5A10B826EE1D7F6E0841" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:to="loc_dei_DocumentPeriodEndDate_D913C93F89FB5A10B826EE1D7F6E0841" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_7E45157A6F0AFAF4BC44EE1D7F6F9235" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_7E45157A6F0AFAF4BC44EE1D7F6F9235" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_C31E07AF097D7A0B4B4DEE1D7F6F5570" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_C31E07AF097D7A0B4B4DEE1D7F6F5570" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_344BFBA1CCB90F71BD9FEE1D7F6FAE0F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_344BFBA1CCB90F71BD9FEE1D7F6FAE0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_BB254304FA67CD3C1A13EE1D7F773E09" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_BB254304FA67CD3C1A13EE1D7F773E09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_176119FC766439251062EE1D7F77E816" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4841F5D6467AFCC1A9FBEE1D7F6ED2EE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_176119FC766439251062EE1D7F77E816" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VestingAxis" xlink:label="loc_us-gaap_VestingAxis_0B91BF59193E6308DAA212FDC9948AC2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:to="loc_us-gaap_VestingAxis_0B91BF59193E6308DAA212FDC9948AC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VestingDomain" xlink:label="loc_us-gaap_VestingDomain_CFC8ACC02FD9801FABBC12FDF09481B3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VestingAxis_0B91BF59193E6308DAA212FDC9948AC2" xlink:to="loc_us-gaap_VestingDomain_CFC8ACC02FD9801FABBC12FDF09481B3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VestingDomain" xlink:label="loc_us-gaap_VestingDomain_CFC8ACC02FD9801FABBC12FDF09481B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VestingAxis_0B91BF59193E6308DAA212FDC9948AC2" xlink:to="loc_us-gaap_VestingDomain_CFC8ACC02FD9801FABBC12FDF09481B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationAwardTrancheOneMember" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember_3F223F5E57CDE36FD84012FE340F292B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_CFC8ACC02FD9801FABBC12FDF09481B3" xlink:to="loc_us-gaap_ShareBasedCompensationAwardTrancheOneMember_3F223F5E57CDE36FD84012FE340F292B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationAwardTrancheTwoMember" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_C5C03C9E990369952A4112FE5C2F8783" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_CFC8ACC02FD9801FABBC12FDF09481B3" xlink:to="loc_us-gaap_ShareBasedCompensationAwardTrancheTwoMember_C5C03C9E990369952A4112FE5C2F8783" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationAwardTrancheThreeMember" xlink:label="loc_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_08FA836CDF5A88D21B4512FE8851242F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_CFC8ACC02FD9801FABBC12FDF09481B3" xlink:to="loc_us-gaap_ShareBasedCompensationAwardTrancheThreeMember_08FA836CDF5A88D21B4512FE8851242F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_ED45F01B6164473503D812F5E0C6A84F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_ED45F01B6164473503D812F5E0C6A84F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C76C2C37877B61C3011612F5E0C7D780_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_ED45F01B6164473503D812F5E0C6A84F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C76C2C37877B61C3011612F5E0C7D780_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C76C2C37877B61C3011612F5E0C7D780" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_ED45F01B6164473503D812F5E0C6A84F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C76C2C37877B61C3011612F5E0C7D780" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EngilityHoldingsIncMember" xlink:label="loc_saic_EngilityHoldingsIncMember_75EFD2300961909F82D512F5E0C764D1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C76C2C37877B61C3011612F5E0C7D780" xlink:to="loc_saic_EngilityHoldingsIncMember_75EFD2300961909F82D512F5E0C764D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_BD57D93280E894EF78CE12F5E0C71AAF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:to="loc_us-gaap_PlanNameAxis_BD57D93280E894EF78CE12F5E0C71AAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_FFCEE0E2D681FF96F3C912F5E0C76B3A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_BD57D93280E894EF78CE12F5E0C71AAF" xlink:to="loc_us-gaap_PlanNameDomain_FFCEE0E2D681FF96F3C912F5E0C76B3A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_FFCEE0E2D681FF96F3C912F5E0C76B3A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_BD57D93280E894EF78CE12F5E0C71AAF" xlink:to="loc_us-gaap_PlanNameDomain_FFCEE0E2D681FF96F3C912F5E0C76B3A" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_TwoThousandAndThirteenEquityIncentivePlanMember" xlink:label="loc_saic_TwoThousandAndThirteenEquityIncentivePlanMember_16987603AED358C8C7D712F5E0C8579F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_FFCEE0E2D681FF96F3C912F5E0C76B3A" xlink:to="loc_saic_TwoThousandAndThirteenEquityIncentivePlanMember_16987603AED358C8C7D712F5E0C8579F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EmployeeStockPurchasePlanMember" xlink:label="loc_saic_EmployeeStockPurchasePlanMember_2A2F2AED5AC88D78B0EC12F5E0C8B304" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_FFCEE0E2D681FF96F3C912F5E0C76B3A" xlink:to="loc_saic_EmployeeStockPurchasePlanMember_2A2F2AED5AC88D78B0EC12F5E0C8B304" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srt_TitleOfIndividualAxis_CA6898787B99D00730B812F5E0C8136C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:to="loc_srt_TitleOfIndividualAxis_CA6898787B99D00730B812F5E0C8136C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_926017084E4E6E0FA81C12F5E0C80CC8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_CA6898787B99D00730B812F5E0C8136C" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_926017084E4E6E0FA81C12F5E0C80CC8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_926017084E4E6E0FA81C12F5E0C80CC8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_CA6898787B99D00730B812F5E0C8136C" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_926017084E4E6E0FA81C12F5E0C80CC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_DirectorMember" xlink:label="loc_srt_DirectorMember_53459355678043CA5FF712F5E0C9D562" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_926017084E4E6E0FA81C12F5E0C80CC8" xlink:to="loc_srt_DirectorMember_53459355678043CA5FF712F5E0C9D562" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_F4BA7A8899D46A7B54AC12F5E0C9506D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:to="loc_us-gaap_AwardTypeAxis_F4BA7A8899D46A7B54AC12F5E0C9506D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_F4BA7A8899D46A7B54AC12F5E0C9506D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_F4BA7A8899D46A7B54AC12F5E0C9506D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_VestingStockAwardsAndEmployeeStockOptionGrantedPriorToFiscalTwentyFifteenMember" xlink:label="loc_saic_VestingStockAwardsAndEmployeeStockOptionGrantedPriorToFiscalTwentyFifteenMember_3BDD5A9109F3E00BB2A412F5E0CAEF89" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_saic_VestingStockAwardsAndEmployeeStockOptionGrantedPriorToFiscalTwentyFifteenMember_3BDD5A9109F3E00BB2A412F5E0CAEF89" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_EmployeeStockOptionGrantedThereafterMember" xlink:label="loc_saic_EmployeeStockOptionGrantedThereafterMember_5A3AAD9F5BFE86D84F5512F5E0CAC620" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_saic_EmployeeStockOptionGrantedThereafterMember_5A3AAD9F5BFE86D84F5512F5E0CAC620" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_VestingStockAwardsGrantedThereafterMember" xlink:label="loc_saic_VestingStockAwardsGrantedThereafterMember_D7DAA74823357C34214812F5E0CAA521" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_saic_VestingStockAwardsGrantedThereafterMember_D7DAA74823357C34214812F5E0CAA521" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_12574D37D02BEFFF4D1112F5E0CA196A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_us-gaap_EmployeeStockOptionMember_12574D37D02BEFFF4D1112F5E0CA196A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_35A0CFD9E1FBEDE4DB4612F5E0CA8545" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_us-gaap_PerformanceSharesMember_35A0CFD9E1FBEDE4DB4612F5E0CA8545" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_VestingStockAwardsMember" xlink:label="loc_saic_VestingStockAwardsMember_2356CA0A76A96C6CD5DB12F5E0CBEAA8" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_saic_VestingStockAwardsMember_2356CA0A76A96C6CD5DB12F5E0CBEAA8" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SharebasedPaymentArrangementMember" xlink:label="loc_saic_SharebasedPaymentArrangementMember_6A0FA8C00F22C11AF01412F5E0CBF7C2" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_saic_SharebasedPaymentArrangementMember_6A0FA8C00F22C11AF01412F5E0CBF7C2" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SharebasedPaymentArrangementPrecombinationMember" xlink:label="loc_saic_SharebasedPaymentArrangementPrecombinationMember_13DC65D7E0D0F583631012F5E0CB3565" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_saic_SharebasedPaymentArrangementPrecombinationMember_13DC65D7E0D0F583631012F5E0CB3565" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SharebasedPaymentArrangementPostcombinationMember" xlink:label="loc_saic_SharebasedPaymentArrangementPostcombinationMember_F69371F6333793DDBA5112F5E0CB457A" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8137E43075A454F1D1F512F5E0C9AC32" xlink:to="loc_saic_SharebasedPaymentArrangementPostcombinationMember_F69371F6333793DDBA5112F5E0CB457A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_2D8DA9316E52EB53C19012F5E0CBB9C9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_C16DB1ABB8BC747DD6D712F5E0C6A467" xlink:to="loc_srt_RangeAxis_2D8DA9316E52EB53C19012F5E0CBB9C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F416A96407836E1F87C112F5E0CB79A7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_2D8DA9316E52EB53C19012F5E0CBB9C9" xlink:to="loc_srt_RangeMember_F416A96407836E1F87C112F5E0CB79A7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_F416A96407836E1F87C112F5E0CB79A7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_2D8DA9316E52EB53C19012F5E0CBB9C9" xlink:to="loc_srt_RangeMember_F416A96407836E1F87C112F5E0CB79A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_41F8725861FA4967C42312F5E0CCBD73" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_F416A96407836E1F87C112F5E0CB79A7" xlink:to="loc_srt_MaximumMember_41F8725861FA4967C42312F5E0CCBD73" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationEquityRightConversionCommonSharesConversionRatio" xlink:label="loc_saic_BusinessCombinationEquityRightConversionCommonSharesConversionRatio_55384E65388ACB97CB2B12F5E0CC5594" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_BusinessCombinationEquityRightConversionCommonSharesConversionRatio_55384E65388ACB97CB2B12F5E0CC5594" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAwardsAssumed" xlink:label="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAwardsAssumed_EE5EAB7B4E8619C2190812F5E0CDA765" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAwardsAssumed_EE5EAB7B4E8619C2190812F5E0CDA765" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantsAssumedWeightedAverageGrantDateFairValue" xlink:label="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantsAssumedWeightedAverageGrantDateFairValue_0EBBAB413AFBE2D021F512F5E0CDEE34" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantsAssumedWeightedAverageGrantDateFairValue_0EBBAB413AFBE2D021F512F5E0CDEE34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation" xlink:label="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_2C9FA9B2067138E07F9E12F5E0CD3C1E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_StockGrantedDuringPeriodValueSharebasedCompensation_2C9FA9B2067138E07F9E12F5E0CD3C1E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost_8F493C8DBA128AF87F6412F5E0CD5F72" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost_8F493C8DBA128AF87F6412F5E0CD5F72" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_55687E1598BEB00BE72912F5E0CD8483" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable_55687E1598BEB00BE72912F5E0CD8483" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_NumberOfStockBasedCompensationPlans" xlink:label="loc_saic_NumberOfStockBasedCompensationPlans_E15200059EEA2ABD64D912F5E0CDE096" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_NumberOfStockBasedCompensationPlans_E15200059EEA2ABD64D912F5E0CDE096" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_CCD8D47D5AF445CD573812F5E0CEBE44" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_CCD8D47D5AF445CD573812F5E0CEBE44" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_1C0BBEF85B74C7BAED4F12F5E0CE92C9" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_dei_DocumentPeriodEndDate_1C0BBEF85B74C7BAED4F12F5E0CE92C9" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PercentageOfStockAwardsVestOrExercisableAfterOneYear" xlink:label="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterOneYear_542AD58C569DFC96EEA412F5E0CE2973" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterOneYear_542AD58C569DFC96EEA412F5E0CE2973" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PercentageOfStockAwardsVestOrExercisableAfterTwoYears" xlink:label="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterTwoYears_4E0BE0CA42356B85D08A12F5E0CE767F" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterTwoYears_4E0BE0CA42356B85D08A12F5E0CE767F" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PercentageOfStockAwardsVestOrExercisableAfterThreeYears" xlink:label="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterThreeYears_F7DB6D4198BF1E40CF3F12F5E0CE6A59" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterThreeYears_F7DB6D4198BF1E40CF3F12F5E0CE6A59" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PercentageOfStockAwardsVestOrExercisableAfterFourYears" xlink:label="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterFourYears_EB94139D9446E4BDE70812F5E0CF1B3B" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_PercentageOfStockAwardsVestOrExercisableAfterFourYears_EB94139D9446E4BDE70812F5E0CF1B3B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_5E0BD3064F9D792B121E12FD37627EA3" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_5E0BD3064F9D792B121E12FD37627EA3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_A9B0740D1616B793DDF312F5E0CF29F7" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_A9B0740D1616B793DDF312F5E0CF29F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_EA9CD520E9C41EB0BD4212F5E0CF75BB" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_EA9CD520E9C41EB0BD4212F5E0CF75BB" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_MaximumRangeOfAwardsOfTargetNumberOfShares" xlink:label="loc_saic_MaximumRangeOfAwardsOfTargetNumberOfShares_B4E13FD9AEC07FF4176412F5E0CF2C82" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_MaximumRangeOfAwardsOfTargetNumberOfShares_B4E13FD9AEC07FF4176412F5E0CF2C82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_996666C19995C58EA3F412F5E0CF63E7" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_996666C19995C58EA3F412F5E0CF63E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_3568E63CB41A926E4B6E12F5E0CFDA3D" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_3568E63CB41A926E4B6E12F5E0CFDA3D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_0F22554011B6CE86365E12F5E0D0AD0A" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_0F22554011B6CE86365E12F5E0D0AD0A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_77739CDBF0FC7602F00012F5E0D07C9F" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_77739CDBF0FC7602F00012F5E0D07C9F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_4D5D2CF5A1F090F7E6C812F5E0D00C63" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_4D5D2CF5A1F090F7E6C812F5E0D00C63" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsLowerThanMinimumPerformance" xlink:label="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsLowerThanMinimumPerformance_F0AB988BB907D19583F512F5E0D034FB" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsLowerThanMinimumPerformance_F0AB988BB907D19583F512F5E0D034FB" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_PercentageOfAwardsPresentedForTargetNumberOfShares" xlink:label="loc_saic_PercentageOfAwardsPresentedForTargetNumberOfShares_08CCB8CAF844DC1B054512F5E0D0D81B" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_PercentageOfAwardsPresentedForTargetNumberOfShares_08CCB8CAF844DC1B054512F5E0D0D81B" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsContingentlyIssuableShares" xlink:label="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsContingentlyIssuableShares_5562017A8F5B5E5994B212F5E0D17092" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_B0AB0C8DD5F11BAD0FC212F5E0CCBF3D" xlink:to="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsContingentlyIssuableShares_5562017A8F5B5E5994B212F5E0D17092" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationScheduleOfPerformanceShareAwardActivityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_688F937E3888DE23A783EE1D7F4543C8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_AE65961D2192212A9B16EE1D7F450E5A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_688F937E3888DE23A783EE1D7F4543C8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_AE65961D2192212A9B16EE1D7F450E5A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_C624409B5B97B64E6A8AEE1D7F45CF3B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_AE65961D2192212A9B16EE1D7F450E5A" xlink:to="loc_us-gaap_AwardTypeAxis_C624409B5B97B64E6A8AEE1D7F45CF3B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CFDC92FB9BB90F1CCB2EEE1D7F4566A1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_C624409B5B97B64E6A8AEE1D7F45CF3B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CFDC92FB9BB90F1CCB2EEE1D7F4566A1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CFDC92FB9BB90F1CCB2EEE1D7F4566A1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_C624409B5B97B64E6A8AEE1D7F45CF3B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CFDC92FB9BB90F1CCB2EEE1D7F4566A1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_BE0AF1ED10C166D5FA86EE1D7F45DB4C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CFDC92FB9BB90F1CCB2EEE1D7F4566A1" xlink:to="loc_us-gaap_PerformanceSharesMember_BE0AF1ED10C166D5FA86EE1D7F45DB4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_36BBB6EEB0F23304A902EE1D7F45AF1C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_688F937E3888DE23A783EE1D7F4543C8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_36BBB6EEB0F23304A902EE1D7F45AF1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_1931F0A1EE50C276CE6FEE1D7F45D345" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_36BBB6EEB0F23304A902EE1D7F45AF1C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_1931F0A1EE50C276CE6FEE1D7F45D345" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_DF34DCD5CBD5C2BFD6DEEE1D7F458E76" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_36BBB6EEB0F23304A902EE1D7F45AF1C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_DF34DCD5CBD5C2BFD6DEEE1D7F458E76" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_22864E436FBC2AFBCF27EE1D7F451422" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_36BBB6EEB0F23304A902EE1D7F45AF1C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_22864E436FBC2AFBCF27EE1D7F451422" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_71399A8A66702006438DEE1D7F455EDE" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_36BBB6EEB0F23304A902EE1D7F45AF1C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_71399A8A66702006438DEE1D7F455EDE" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustment" xlink:label="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustment_C39EFC0D18E432BB997DEE1D7F451BF3" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_36BBB6EEB0F23304A902EE1D7F45AF1C" xlink:to="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustment_C39EFC0D18E432BB997DEE1D7F451BF3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_59CCCB60678FA25D93B4EE1D7F457279" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_688F937E3888DE23A783EE1D7F4543C8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_59CCCB60678FA25D93B4EE1D7F457279" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_FBF83088D6B924C97422EE1D7F453E21" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_59CCCB60678FA25D93B4EE1D7F457279" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_FBF83088D6B924C97422EE1D7F453E21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_FA3C73AC69EE340DAA50EE1D7F451C48" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_59CCCB60678FA25D93B4EE1D7F457279" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_FA3C73AC69EE340DAA50EE1D7F451C48" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_2E6832DA09142E202491EE1D7F45736F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_59CCCB60678FA25D93B4EE1D7F457279" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_2E6832DA09142E202491EE1D7F45736F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_D0FDDE043F259094DC5CEE1D7F457DD9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_59CCCB60678FA25D93B4EE1D7F457279" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_D0FDDE043F259094DC5CEE1D7F457DD9" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentInPeriodWeightedAverageGrantDateFairValue_313B097E8A08BD431C6AEE1D7F457A4F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_59CCCB60678FA25D93B4EE1D7F457279" xlink:to="loc_saic_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentInPeriodWeightedAverageGrantDateFairValue_313B097E8A08BD431C6AEE1D7F457A4F" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_EBD020AC71C169EBE379EE1D7F4560C0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_688F937E3888DE23A783EE1D7F4543C8" xlink:to="loc_dei_DocumentPeriodEndDate_EBD020AC71C169EBE379EE1D7F4560C0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationScheduleOfSharedBasedCompensationCostRelatedToStockOptionsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationScheduleOfStockBasedCompensationExpenseAndRelatedTaxBenefitsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_3D28717AE19FA47C725F10CDF2E0C81C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_710F9C8566DBC8A3694610CDF2DEEA92" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_3D28717AE19FA47C725F10CDF2E0C81C" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_710F9C8566DBC8A3694610CDF2DEEA92" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_89CC93C021B58F97CCEB10CDF2DF24DB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_710F9C8566DBC8A3694610CDF2DEEA92" xlink:to="loc_us-gaap_AwardTypeAxis_89CC93C021B58F97CCEB10CDF2DF24DB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2DEECA4CD0BC9CD219C010CDF2DFCE73_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_89CC93C021B58F97CCEB10CDF2DF24DB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2DEECA4CD0BC9CD219C010CDF2DFCE73_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2DEECA4CD0BC9CD219C010CDF2DFCE73" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_89CC93C021B58F97CCEB10CDF2DF24DB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2DEECA4CD0BC9CD219C010CDF2DFCE73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_1BC13D723102E5627DCA10CDF2DFFDEE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2DEECA4CD0BC9CD219C010CDF2DFCE73" xlink:to="loc_us-gaap_EmployeeStockOptionMember_1BC13D723102E5627DCA10CDF2DFFDEE" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_VestingStockAwardsMember" xlink:label="loc_saic_VestingStockAwardsMember_A48825F193E0D9E404EB10CDF2E0D54D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2DEECA4CD0BC9CD219C010CDF2DFCE73" xlink:to="loc_saic_VestingStockAwardsMember_A48825F193E0D9E404EB10CDF2E0D54D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_B7B46F3452DDFA4113EC10CDF2E0B444" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2DEECA4CD0BC9CD219C010CDF2DFCE73" xlink:to="loc_us-gaap_PerformanceSharesMember_B7B46F3452DDFA4113EC10CDF2E0B444" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_70010A65661F13441A4B10CDF2E0B26C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_3D28717AE19FA47C725F10CDF2E0C81C" xlink:to="loc_dei_DocumentPeriodEndDate_70010A65661F13441A4B10CDF2E0B26C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_F692B9054C18217F806010CDF2E0BAA8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_3D28717AE19FA47C725F10CDF2E0C81C" xlink:to="loc_us-gaap_ShareBasedCompensation_F692B9054C18217F806010CDF2E0BAA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_E40D4C016DE9F78B929010CDF2E1F38D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_3D28717AE19FA47C725F10CDF2E0C81C" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_E40D4C016DE9F78B929010CDF2E1F38D" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationScheduleOfStockOptionActivityDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationScheduleOfVestingStockAwardActivityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8283C8AC163D5ABA0873EE1D7F5E2BB9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_07E5C33D9CD83CA0D500EE1D7F5DE62F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8283C8AC163D5ABA0873EE1D7F5E2BB9" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_07E5C33D9CD83CA0D500EE1D7F5DE62F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_338F1E9A31816091C47BEE1D7F5D69C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_07E5C33D9CD83CA0D500EE1D7F5DE62F" xlink:to="loc_us-gaap_AwardTypeAxis_338F1E9A31816091C47BEE1D7F5D69C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AD64E84D074FA23E95E7EE1D7F5E70E7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_338F1E9A31816091C47BEE1D7F5D69C1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AD64E84D074FA23E95E7EE1D7F5E70E7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AD64E84D074FA23E95E7EE1D7F5E70E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_338F1E9A31816091C47BEE1D7F5D69C1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AD64E84D074FA23E95E7EE1D7F5E70E7" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_VestingStockAwardsMember" xlink:label="loc_saic_VestingStockAwardsMember_939E75D7A87E0C98BC7AEE1D7F5EBFD3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_AD64E84D074FA23E95E7EE1D7F5E70E7" xlink:to="loc_saic_VestingStockAwardsMember_939E75D7A87E0C98BC7AEE1D7F5EBFD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_9B7BB59D035617427012EE1D7F5E3AD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8283C8AC163D5ABA0873EE1D7F5E2BB9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_9B7BB59D035617427012EE1D7F5E3AD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_66100F451278A40BC5B0EE1D7F5F1094" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_9B7BB59D035617427012EE1D7F5E3AD0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_66100F451278A40BC5B0EE1D7F5F1094" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_268E716F037B7AF13C65EE1D7F5F50D7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_9B7BB59D035617427012EE1D7F5E3AD0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_268E716F037B7AF13C65EE1D7F5F50D7" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAwardsAssumed" xlink:label="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAwardsAssumed_97A768D71CD93EAFB6B6EE1D7F5FE52F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_9B7BB59D035617427012EE1D7F5E3AD0" xlink:to="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAwardsAssumed_97A768D71CD93EAFB6B6EE1D7F5FE52F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_2EC1858816C650C5E2E5EE1D7F5FBD23" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_9B7BB59D035617427012EE1D7F5E3AD0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_2EC1858816C650C5E2E5EE1D7F5FBD23" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC3A75F26471AF7DD642EE1D7F60804C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_9B7BB59D035617427012EE1D7F5E3AD0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC3A75F26471AF7DD642EE1D7F60804C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_68D43734B0A2C44AAF38EE1D7F60A57C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8283C8AC163D5ABA0873EE1D7F5E2BB9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_68D43734B0A2C44AAF38EE1D7F60A57C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_FA2F624274BA9DE34FD5EE1D7F609A02" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_68D43734B0A2C44AAF38EE1D7F60A57C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_FA2F624274BA9DE34FD5EE1D7F609A02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_DBDC39E3D6C40A8BC1AAEE1D7F60D32C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_68D43734B0A2C44AAF38EE1D7F60A57C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_DBDC39E3D6C40A8BC1AAEE1D7F60D32C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantsAssumedWeightedAverageGrantDateFairValue" xlink:label="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantsAssumedWeightedAverageGrantDateFairValue_6E9A38A2F9FC80C0E873EE1D7F61AE70" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_68D43734B0A2C44AAF38EE1D7F60A57C" xlink:to="loc_saic_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsGrantsAssumedWeightedAverageGrantDateFairValue_6E9A38A2F9FC80C0E873EE1D7F61AE70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_70DBFC863AB4543B52EAEE1D7F61CB59" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_68D43734B0A2C44AAF38EE1D7F60A57C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_70DBFC863AB4543B52EAEE1D7F61CB59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_EB068205FFE17826B733EE1D7F614178" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_68D43734B0A2C44AAF38EE1D7F60A57C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_EB068205FFE17826B733EE1D7F614178" xlink:type="arc" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_4E301410A526A722BD71EE1D7F611F55" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8283C8AC163D5ABA0873EE1D7F5E2BB9" xlink:to="loc_dei_DocumentPeriodEndDate_4E301410A526A722BD71EE1D7F611F55" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/StockBasedCompensationTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.saic.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable_7118C2E3BD0BD38AE32707C84F5460A4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_SubsequentEventTable_7118C2E3BD0BD38AE32707C84F5460A4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_6A9A9DDB4EAA1C7406ED07CCD57B387D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_7118C2E3BD0BD38AE32707C84F5460A4" xlink:to="loc_us-gaap_DebtInstrumentAxis_6A9A9DDB4EAA1C7406ED07CCD57B387D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0DE90657DB3724BE263407CCD583422C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6A9A9DDB4EAA1C7406ED07CCD57B387D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0DE90657DB3724BE263407CCD583422C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0DE90657DB3724BE263407CCD583422C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6A9A9DDB4EAA1C7406ED07CCD57B387D" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0DE90657DB3724BE263407CCD583422C" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_FourPointEightSevenFivePercentSeniorNotesDue2028Member" xlink:label="loc_saic_FourPointEightSevenFivePercentSeniorNotesDue2028Member_8F8DB0189E22E6CE9B7A07CD870223E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0DE90657DB3724BE263407CCD583422C" xlink:to="loc_saic_FourPointEightSevenFivePercentSeniorNotesDue2028Member_8F8DB0189E22E6CE9B7A07CD870223E3" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_IncrementalTermLoanFacilityMember" xlink:label="loc_saic_IncrementalTermLoanFacilityMember_7D134B8E844D8E47DB7A07CEF2974339" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0DE90657DB3724BE263407CCD583422C" xlink:to="loc_saic_IncrementalTermLoanFacilityMember_7D134B8E844D8E47DB7A07CEF2974339" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_AccountsReceivableFacilityMember" xlink:label="loc_saic_AccountsReceivableFacilityMember_A67C9552C33AABF3261707D95B3E3A6E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0DE90657DB3724BE263407CCD583422C" xlink:to="loc_saic_AccountsReceivableFacilityMember_A67C9552C33AABF3261707D95B3E3A6E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_EEA2FA48260A0AF8E6BD07C92564764F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_7118C2E3BD0BD38AE32707C84F5460A4" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_EEA2FA48260A0AF8E6BD07C92564764F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1F53A89635DA29A345EC07C92569B8DA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_EEA2FA48260A0AF8E6BD07C92564764F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1F53A89635DA29A345EC07C92569B8DA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1F53A89635DA29A345EC07C92569B8DA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_EEA2FA48260A0AF8E6BD07C92564764F" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1F53A89635DA29A345EC07C92569B8DA" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_UnisysFederalMember" xlink:label="loc_saic_UnisysFederalMember_D86DFA5B90BA854A8F0407C9781A179B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1F53A89635DA29A345EC07C92569B8DA" xlink:to="loc_saic_UnisysFederalMember_D86DFA5B90BA854A8F0407C9781A179B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_40FE9D6C8117DA6F7EEE07C84F56A708" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_7118C2E3BD0BD38AE32707C84F5460A4" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_40FE9D6C8117DA6F7EEE07C84F56A708" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_9909BD2388F423B6F98607C84F581C51_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_40FE9D6C8117DA6F7EEE07C84F56A708" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_9909BD2388F423B6F98607C84F581C51_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_9909BD2388F423B6F98607C84F581C51" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_40FE9D6C8117DA6F7EEE07C84F56A708" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_9909BD2388F423B6F98607C84F581C51" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_A6B6A4AE1138A0E6B38D07C88AB7C2B2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_9909BD2388F423B6F98607C84F581C51" xlink:to="loc_us-gaap_SubsequentEventMember_A6B6A4AE1138A0E6B38D07C88AB7C2B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax_DF601F757805772FCFA007E2051B04A5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax_DF601F757805772FCFA007E2051B04A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_118CAD86DEA86E51FEE007C7BB4A3626" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_118CAD86DEA86E51FEE007C7BB4A3626" xlink:type="arc" />
    <link:loc xlink:href="saic-20200131.xsd#saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts" xlink:label="loc_saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts_B6CA0D787E835C9700D207CA84F658DC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_saic_BusinessCombinationAcquisitionAndIntegrationRelatedCosts_B6CA0D787E835C9700D207CA84F658DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_1AC5E4156409D05F979F07CC26572088" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_1AC5E4156409D05F979F07CC26572088" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_E056AA77C187D02475AF07CF9C80D4C0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_E056AA77C187D02475AF07CF9C80D4C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="loc_us-gaap_DebtInstrumentTerm_4292DBFA3C23D01737D007D1C6853C96" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_DebtInstrumentTerm_4292DBFA3C23D01737D007D1C6853C96" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsReceivableFromSecuritization" xlink:label="loc_us-gaap_AccountsReceivableFromSecuritization_BE5F0361D1A3CE692D4707D751CB6F70" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_AccountsReceivableFromSecuritization_BE5F0361D1A3CE692D4707D751CB6F70" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromAccountsReceivableSecuritization" xlink:label="loc_us-gaap_ProceedsFromAccountsReceivableSecuritization_CFDB56295D6176273B2F07D9C92B4F53" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_BCE3CF212A56F048D10D07C84F5E5238" xlink:to="loc_us-gaap_ProceedsFromAccountsReceivableSecuritization_CFDB56295D6176273B2F07D9C92B4F53" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.saic.com/role/SubsequentEventsNotes" xlink:type="extended" />
</link:linkbase>
