<?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>0001669918</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001169561</issuerCik>
            <issuerName>COMMVAULT SYSTEMS INC.</issuerName>
            <secFileNumber>001-33026</secFileNumber>
            <issuerAddress>
                <ns2:street1>1 Commvault Way</ns2:street1>
                <ns2:city>Tinton Falls</ns2:city>
                <ns2:stateOrCountry>NJ</ns2:stateOrCountry>
                <ns2:zipCode>07724</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>(732) 870-4000</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>NICOLA ADAMO</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Director</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>E*TRADE FINANCIAL CORPORATION</name>
                <address>
                    <ns2:street1>3 EDISON DRIVE</ns2:street1>
                    <ns2:city>ALPHARETTA</ns2:city>
                    <ns2:stateOrCountry>GA</ns2:stateOrCountry>
                    <ns2:zipCode>30005</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>1000</noOfUnitsSold>
            <aggregateMarketValue>67000.00</aggregateMarketValue>
            <noOfUnitsOutstanding>43973836</noOfUnitsOutstanding>
            <approxSaleDate>05/22/2023</approxSaleDate>
            <securitiesExchangeName>NASD</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>08/22/2019</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted Stock</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>1000</amountOfSecuritiesAcquired>
            <paymentDate>08/22/2019</paymentDate>
            <natureOfPayment>Not Applicable</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>05/22/2023</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>02/03/2023</planAdoptionDate>
            </planAdoptionDates>
            <signature>NICOLA ADAMO</signature>
        </noticeSignature>
    </formData>
</edgarSubmission>
[{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 3210}]
144
0001669918
XXXXXXXX
LIVE
0001169561
COMMVAULT SYSTEMS INC.
001-33026
1 Commvault Way
Tinton Falls
NJ
07724
(732) 870-4000
NICOLA ADAMO
Director
Common
E*TRADE FINANCIAL CORPORATION
3 EDISON DRIVE
ALPHARETTA
GA
30005
1000
67000.00
43973836
05/22/2023
NASD
Common
08/22/2019
Restricted Stock
Issuer
N
1000
08/22/2019
Not Applicable
Y
05/22/2023
02/03/2023
NICOLA ADAMO