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      <link:roleType id="SegmentInformationScheduleofSelectedFinancialDatabyReportableSegmentDetails" roleURI="http://www.aciworldwide.com/role/SegmentInformationScheduleofSelectedFinancialDatabyReportableSegmentDetails">
        <link:definition>9955540 - Disclosure - Segment Information - Schedule of Selected Financial Data by Reportable Segment (Details)</link:definition>
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        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
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      <link:roleType id="SegmentInformationSelectedFinancialDataRevenuesandLonglivedAssetsDetails" roleURI="http://www.aciworldwide.com/role/SegmentInformationSelectedFinancialDataRevenuesandLonglivedAssetsDetails">
        <link:definition>9955541 - Disclosure - Segment Information - Selected Financial Data, Revenues and Long lived Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
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      <link:roleType id="IncomeTaxesDetails" roleURI="http://www.aciworldwide.com/role/IncomeTaxesDetails">
        <link:definition>9955542 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="aciw_SoftwareAsServiceAndPlatformAsServiceMember" abstract="true" name="SoftwareAsServiceAndPlatformAsServiceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_AmortizationExcludingOperatingLeasesAndDebtIssuanceCosts" abstract="false" name="AmortizationExcludingOperatingLeasesAndDebtIssuanceCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_NetIncreaseDecreaseInSettlementAssetsAndLiabilities" abstract="false" name="NetIncreaseDecreaseInSettlementAssetsAndLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_SettlementDepositsCurrent" abstract="false" name="SettlementDepositsCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_SettlementAssetsandLiabilitiesPolicyPolicyTextBlock" abstract="false" name="SettlementAssetsandLiabilitiesPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="aciw_OffBalanceSheetSettlementAccountsPolicyPolicyTextBlock" abstract="false" name="OffBalanceSheetSettlementAccountsPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="aciw_ScheduleOfShareBasedPaymentAwardOtherThanStockOptionsValuationAssumptionsTableTextBlock" abstract="false" name="ScheduleOfShareBasedPaymentAwardOtherThanStockOptionsValuationAssumptionsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="aciw_PaymentSoftwareMember" abstract="true" name="PaymentSoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_BillersMember" abstract="true" name="BillersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_IndiaPaymentTechnologyAndServicesCompanyMember" abstract="true" name="IndiaPaymentTechnologyAndServicesCompanyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_SettlementFundsBalance" abstract="false" name="SettlementFundsBalance" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_EquityMethodInvestmentPercentageSold" abstract="false" name="EquityMethodInvestmentPercentageSold" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="aciw_AccruedReceivablesNet" abstract="false" name="AccruedReceivablesNet" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_ChangeinContractwithCustomerLiabilityRollForward" abstract="true" name="ChangeinContractwithCustomerLiabilityRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_ContractWithCustomerLiabilityAdditions" abstract="false" name="ContractWithCustomerLiabilityAdditions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_ContractWithCustomerLiabilityRecognitionOfRevenue" abstract="false" name="ContractWithCustomerLiabilityRecognitionOfRevenue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_ContractWithCustomerLiabilityForeignCurrencyTranslation" abstract="false" name="ContractWithCustomerLiabilityForeignCurrencyTranslation" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_TermLoansMember" abstract="true" name="TermLoansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_OverdraftFacilityMember" abstract="true" name="OverdraftFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_CreditAgreementMember" abstract="true" name="CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_RefinanceAmendmentMember" abstract="true" name="RefinanceAmendmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_A5.750SeniorNotesDue2026Member" abstract="true" name="A5.750SeniorNotesDue2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_LenderAdditionAndAcknowledgementAgreementMember" abstract="true" name="LenderAdditionAndAcknowledgementAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_MultiYearLicenseAgreementMember" abstract="true" name="MultiYearLicenseAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_VariableRateOptionsAxis" abstract="true" name="VariableRateOptionsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="aciw_VariableRateOptionsDomain" abstract="true" name="VariableRateOptionsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_VariableRateOptionOneMember" abstract="true" name="VariableRateOptionOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_VariableRateOptionTwoMember" abstract="true" name="VariableRateOptionTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_ParentCompanyAndDomesticSubsidiariesMember" abstract="true" name="ParentCompanyAndDomesticSubsidiariesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_ForeignSubsidiariesMember" abstract="true" name="ForeignSubsidiariesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_PercentageOfCapitalStockPledgedAsCollateral" abstract="false" name="PercentageOfCapitalStockPledgedAsCollateral" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="aciw_DebtInstrumentConsolidatedTotalNetLeverageRatio" abstract="false" name="DebtInstrumentConsolidatedTotalNetLeverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="aciw_DebtInstrumentConsolidatedSeniorSecuredNetLeverageRatio" abstract="false" name="DebtInstrumentConsolidatedSeniorSecuredNetLeverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="aciw_DebtInstrumentConsolidatedInterestCoverageRatio" abstract="false" name="DebtInstrumentConsolidatedInterestCoverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="aciw_DebtInstrumentIssuePricePercentageOfPrincipalAmount" abstract="false" name="DebtInstrumentIssuePricePercentageOfPrincipalAmount" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="aciw_LongTermDebtMaturityAfterYearFour" abstract="false" name="LongTermDebtMaturityAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_SoftwareMember" abstract="true" name="SoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_SoftwareAcquiredOrDevelopedForInternalUseMember" abstract="true" name="SoftwareAcquiredOrDevelopedForInternalUseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_SoftwareAcquiredOrDevelopedForResaleMember" abstract="true" name="SoftwareAcquiredOrDevelopedForResaleMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_OtherFiniteLivedIntangibleAssetsMember" abstract="true" name="OtherFiniteLivedIntangibleAssetsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour" abstract="false" name="FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_EmployeeStockPurchasePlanTwentySeventeenMember" abstract="true" name="EmployeeStockPurchasePlanTwentySeventeenMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_TotalShareholderReturnMember" abstract="true" name="TotalShareholderReturnMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementsByShareBasedPaymentAwardTotalShareholderReturnMultiplier" abstract="false" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardTotalShareholderReturnMultiplier" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementsbyShareBasedPaymentAwardPerformanceSharesMaximumTarget" abstract="false" name="ShareBasedCompensationArrangementsbyShareBasedPaymentAwardPerformanceSharesMaximumTarget" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_MonteCarloSimulationValuationModelMember" abstract="true" name="MonteCarloSimulationValuationModelMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_TreasuryStockSharesAcquiredToDate" abstract="false" name="TreasuryStockSharesAcquiredToDate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="aciw_TreasuryStockValueAcquiredCostMethodToDate" abstract="false" name="TreasuryStockValueAcquiredCostMethodToDate" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_NumberOfReportableSegmentsNotDisclosedFlag" abstract="false" name="NumberOfReportableSegmentsNotDisclosedFlag" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_InterchangeCosts" abstract="false" name="InterchangeCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_GlobalTechnologyAndInnovationCosts" abstract="false" name="GlobalTechnologyAndInnovationCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_SegmentAdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" abstract="false" name="SegmentAdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_CorporateAndUnallocatedIncomeExpense" abstract="false" name="CorporateAndUnallocatedIncomeExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_BillerPaymentsMember" abstract="true" name="BillerPaymentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_MerchantPaymentsMember" abstract="true" name="MerchantPaymentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_PaymentsIntelligenceMember" abstract="true" name="PaymentsIntelligenceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_RealTimePaymentsMember" abstract="true" name="RealTimePaymentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_IssuingAndAcquiringMember" abstract="true" name="IssuingAndAcquiringMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_SoftwareAndPlatformServiceMember" abstract="true" name="SoftwareAndPlatformServiceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
