<SEC-DOCUMENT>0001950047-25-007122.txt : 20250915
<SEC-HEADER>0001950047-25-007122.hdr.sgml : 20250915
<ACCEPTANCE-DATETIME>20250915162721
ACCESSION NUMBER:		0001950047-25-007122
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20250915
DATE AS OF CHANGE:		20250915

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Klaviyo, Inc.
		CENTRAL INDEX KEY:			0001835830
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		ORGANIZATION NAME:           	06 Technology
		EIN:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	001-41806
		FILM NUMBER:		251314649

	BUSINESS ADDRESS:	
		STREET 1:		125 SUMMER STREET, FLOOR 6
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
		BUSINESS PHONE:		800-338-1744

	MAIL ADDRESS:	
		STREET 1:		125 SUMMER STREET, FLOOR 6
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110

REPORTING-OWNER:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Rowland Stephen Eric
		CENTRAL INDEX KEY:			0001639368
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		144

	MAIL ADDRESS:	
		STREET 1:		1601 TRAPELO ROAD
		STREET 2:		SUITE 116
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
</SEC-HEADER>
<DOCUMENT>
<TYPE>144
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
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    <headerData>
        <submissionType>144</submissionType>
        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001639368</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
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            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
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    <formData>
        <issuerInfo>
            <issuerCik>0001835830</issuerCik>
            <issuerName>Klaviyo, Inc.</issuerName>
            <secFileNumber>001-41806</secFileNumber>
            <issuerAddress>
                <ns2:street1>125 Summer Street, 6th Floor</ns2:street1>
                <ns2:city>Boston</ns2:city>
                <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                <ns2:zipCode>02110</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>6172131788</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>STEPHEN ROWLAND</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC Executive Financial Services</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>8th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>7105</noOfUnitsSold>
            <aggregateMarketValue>221604.95</aggregateMarketValue>
            <noOfUnitsOutstanding>116897730</noOfUnitsOutstanding>
            <approxSaleDate>09/15/2025</approxSaleDate>
            <securitiesExchangeName>NYSE</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>08/15/2025</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted Stock Units</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>7105</amountOfSecuritiesAcquired>
            <paymentDate>08/15/2025</paymentDate>
            <natureOfPayment>N/A</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for STEPHEN ROWLAND</name>
                <address>
                    <ns2:street1>125 Summer Street, 6th Floor</ns2:street1>
                    <ns2:city>Boston</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>02110</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/18/2025</saleDate>
            <amountOfSecuritiesSold>7105</amountOfSecuritiesSold>
            <grossProceeds>223528.27</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for STEPHEN ROWLAND</name>
                <address>
                    <ns2:street1>125 Summer Street, 6th Floor</ns2:street1>
                    <ns2:city>Boston</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>02110</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/15/2025</saleDate>
            <amountOfSecuritiesSold>7079</amountOfSecuritiesSold>
            <grossProceeds>223446.27</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for STEPHEN ROWLAND</name>
                <address>
                    <ns2:street1>125 Summer Street, 6th Floor</ns2:street1>
                    <ns2:city>Boston</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>02110</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>06/16/2025</saleDate>
            <amountOfSecuritiesSold>7079</amountOfSecuritiesSold>
            <grossProceeds>244619.43</grossProceeds>
        </securitiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>09/15/2025</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>11/22/2024</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Stephen Rowland</signature>
        </noticeSignature>
    </formData>
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</SEC-DOCUMENT>
