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  <xs:element id="qlys_ScannerAppliancesAndOtherComputerEquipmentNotPlacedInServiceMember" abstract="true" name="ScannerAppliancesAndOtherComputerEquipmentNotPlacedInServiceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_ESPPSharesMember" abstract="true" name="ESPPSharesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_CashCashEquivalentsAndShorttermAndLongtermInvestmentsPolicyPolicyTextBlock" abstract="false" name="CashCashEquivalentsAndShorttermAndLongtermInvestmentsPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="qlys_CashAndCashEquivalentsAndDebtSecuritiesAvailableforsaleAmortizedCostToFairValueTableTextBlock" abstract="false" name="CashAndCashEquivalentsAndDebtSecuritiesAvailableforsaleAmortizedCostToFairValueTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="qlys_AssetsAndLiabilitiesLesseeTableTextBlock" abstract="false" name="AssetsAndLiabilitiesLesseeTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="qlys_PresidentAndChiefExecutiveOfficerMember" abstract="true" name="PresidentAndChiefExecutiveOfficerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_DescriptionOfBusinessPolicyPolicyTextBlock" abstract="false" name="DescriptionOfBusinessPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="qlys_AssetAcquisitionConsiderationTransferredPayable" abstract="false" name="AssetAcquisitionConsiderationTransferredPayable" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_StockRepurchaseProgramAdditionalAuthorizedAmount" abstract="false" name="StockRepurchaseProgramAdditionalAuthorizedAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_DeferredLiabilitiesRightofuseAssets" abstract="false" name="DeferredLiabilitiesRightofuseAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_DeferredTaxAssetsOperatingLeaseLiabilities" abstract="false" name="DeferredTaxAssetsOperatingLeaseLiabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_TimeBasedSharedBasedCompensationMember" abstract="true" name="TimeBasedSharedBasedCompensationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_DeferredTaxLiabilitiesDeferredCommission" abstract="false" name="DeferredTaxLiabilitiesDeferredCommission" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetNumberOfShares" abstract="false" name="SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetNumberOfShares" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="qlys_DepreciationDepletionAndAmortizationExcludingIntangibleAssetAmortization" abstract="false" name="DepreciationDepletionAndAmortizationExcludingIntangibleAssetAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_EmployeeStockPurchasePlanSharesMember" abstract="true" name="EmployeeStockPurchasePlanSharesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_AssetAcquisitionAcquisitionRelatedCosts" abstract="false" name="AssetAcquisitionAcquisitionRelatedCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_ForeignExchangeContractsForGBPAndEuroMember" abstract="true" name="ForeignExchangeContractsForGBPAndEuroMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_SecurityDepositsMember" abstract="true" name="SecurityDepositsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_PropertyPlantAndEquipmentAndOperatingLeaseRightofuseAssets" abstract="false" name="PropertyPlantAndEquipmentAndOperatingLeaseRightofuseAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="qlys_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreasePercentOfSharesOutstanding" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreasePercentOfSharesOutstanding" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="qlys_SharebasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingNumber" abstract="false" name="SharebasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingNumber" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="qlys_ExecutiveOfficer4Member" abstract="true" name="ExecutiveOfficer4Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_ExecutiveOfficer1Member" abstract="true" name="ExecutiveOfficer1Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_BlueHexagonIncMember" abstract="true" name="BlueHexagonIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="qlys_AssembledWorkforceMember" abstract="true" name="AssembledWorkforceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
</xs:schema>
