<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:ns2="http://www.sec.gov/edgar/common">
    <headerData>
        <submissionType>144</submissionType>
        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001489550</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001633978</issuerCik>
            <issuerName>LUMENTUM HOLDINGS INC.</issuerName>
            <secFileNumber>001-36861</secFileNumber>
            <issuerAddress>
                <ns2:street1>1001 Ridder Park Drive</ns2:street1>
                <ns2:city>San Jose</ns2:city>
                <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                <ns2:zipCode>95131</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>(408) 546-5483</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>WUPEN YUEN</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>821</noOfUnitsSold>
            <aggregateMarketValue>192228.94</aggregateMarketValue>
            <noOfUnitsOutstanding>70900000</noOfUnitsOutstanding>
            <approxSaleDate>11/17/2025</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>11/15/2024</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted Stock</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>ISSUER</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>821</amountOfSecuritiesAcquired>
            <paymentDate>11/15/2024</paymentDate>
            <natureOfPayment>Not Applicable</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>WUPEN YUEN</name>
                <address>
                    <ns2:street1>1001 Ridder Park Drive</ns2:street1>
                    <ns2:city>San Jose</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>95131</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/27/2025</saleDate>
            <amountOfSecuritiesSold>3281</amountOfSecuritiesSold>
            <grossProceeds>409665.66</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>WUPEN YUEN</name>
                <address>
                    <ns2:street1>1001 Ridder Park Drive</ns2:street1>
                    <ns2:city>San Jose</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>95131</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/26/2025</saleDate>
            <amountOfSecuritiesSold>3282</amountOfSecuritiesSold>
            <grossProceeds>408247.98</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>WUPEN YUEN</name>
                <address>
                    <ns2:street1>1001 Ridder Park Drive</ns2:street1>
                    <ns2:city>San Jose</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>95131</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/25/2025</saleDate>
            <amountOfSecuritiesSold>3282</amountOfSecuritiesSold>
            <grossProceeds>391378.50</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>WUPEN YUEN</name>
                <address>
                    <ns2:street1>1001 Ridder Park Drive</ns2:street1>
                    <ns2:city>San Jose</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>95131</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/19/2025</saleDate>
            <amountOfSecuritiesSold>109</amountOfSecuritiesSold>
            <grossProceeds>12818.40</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>WUPEN YUEN</name>
                <address>
                    <ns2:street1>1001 Ridder Park Drive</ns2:street1>
                    <ns2:city>San Jose</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>95131</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/18/2025</saleDate>
            <amountOfSecuritiesSold>109</amountOfSecuritiesSold>
            <grossProceeds>12693.05</grossProceeds>
        </securitiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>11/17/2025</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>02/11/2025</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Wupen Yuen</signature>
        </noticeSignature>
    </formData>
</edgarSubmission>
