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        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001471798</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0000007431</issuerCik>
            <issuerName>ARMSTRONG WORLD INDUSTRIES INC.</issuerName>
            <secFileNumber>001-02116</secFileNumber>
            <issuerAddress>
                <ns2:street1>2500 Columbia Avenue</ns2:street1>
                <ns2:city>Lancaster</ns2:city>
                <ns2:stateOrCountry>PA</ns2:stateOrCountry>
                <ns2:zipCode>17603</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>(717) 397-0611</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>JAMES C MELVILLE</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Director</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>10000</noOfUnitsSold>
            <aggregateMarketValue>1260075.00</aggregateMarketValue>
            <noOfUnitsOutstanding>43700062</noOfUnitsOutstanding>
            <approxSaleDate>08/02/2024</approxSaleDate>
            <securitiesExchangeName>NYSE</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>06/26/2020</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>1465</amountOfSecuritiesAcquired>
            <paymentDate>06/26/2020</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>06/17/2022</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>1406</amountOfSecuritiesAcquired>
            <paymentDate>06/17/2022</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>06/23/2014</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>752</amountOfSecuritiesAcquired>
            <paymentDate>06/23/2014</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>07/13/2018</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>1558</amountOfSecuritiesAcquired>
            <paymentDate>07/13/2018</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>07/12/2019</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>1064</amountOfSecuritiesAcquired>
            <paymentDate>07/12/2019</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>06/25/2021</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>992</amountOfSecuritiesAcquired>
            <paymentDate>06/25/2021</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>06/16/2023</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>1778</amountOfSecuritiesAcquired>
            <paymentDate>06/16/2023</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>07/28/2022</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>229</amountOfSecuritiesAcquired>
            <paymentDate>07/28/2022</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>02/28/2012</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted stock vesting under a registered plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>756</amountOfSecuritiesAcquired>
            <paymentDate>02/28/2012</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>08/02/2024</noticeDate>
            <planAdoptionDates/>
            <signature>/s/ James C. Melville</signature>
        </noticeSignature>
    </formData>
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144
0001471798
XXXXXXXX
LIVE
0000007431
ARMSTRONG WORLD INDUSTRIES INC.
001-02116
2500 Columbia Avenue
Lancaster
PA
17603
(717) 397-0611
JAMES C MELVILLE
Director
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
8th Floor
New York
NY
10004
10000
1260075.00
43700062
08/02/2024
NYSE
Common
06/26/2020
Restricted stock vesting under a registered plan
Issuer
N
1465
06/26/2020
Services Rendered
Common
06/17/2022
Restricted stock vesting under a registered plan
Issuer
N
1406
06/17/2022
Services Rendered
Common
06/23/2014
Restricted stock vesting under a registered plan
Issuer
N
752
06/23/2014
Services Rendered
Common
07/13/2018
Restricted stock vesting under a registered plan
Issuer
N
1558
07/13/2018
Services Rendered
Common
07/12/2019
Restricted stock vesting under a registered plan
Issuer
N
1064
07/12/2019
Services Rendered
Common
06/25/2021
Restricted stock vesting under a registered plan
Issuer
N
992
06/25/2021
Services Rendered
Common
06/16/2023
Restricted stock vesting under a registered plan
Issuer
N
1778
06/16/2023
Services Rendered
Common
07/28/2022
Restricted stock vesting under a registered plan
Issuer
N
229
07/28/2022
Services Rendered
Common
02/28/2012
Restricted stock vesting under a registered plan
Issuer
N
756
02/28/2012
Services Rendered
Y
08/02/2024
/s/ James C. Melville