<SEC-DOCUMENT>0000911177-24-000102.txt : 20241108
<SEC-HEADER>0000911177-24-000102.hdr.sgml : 20241108
<ACCEPTANCE-DATETIME>20241108162307
ACCESSION NUMBER:		0000911177-24-000102
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20241106
FILED AS OF DATE:		20241108
DATE AS OF CHANGE:		20241108

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Green Emily Nagle
		CENTRAL INDEX KEY:			0001553453
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23211
		FILM NUMBER:		241440956

	MAIL ADDRESS:	
		STREET 1:		CASELLA WASTE SYSTEMS
		STREET 2:		25 GREENS HILL LANE
		CITY:			RUTLAND
		STATE:			VT
		ZIP:			05701

	FORMER NAME:	
		FORMER CONFORMED NAME:	Nagle Emily K
		DATE OF NAME CHANGE:	20120702

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CASELLA WASTE SYSTEMS INC
		CENTRAL INDEX KEY:			0000911177
		STANDARD INDUSTRIAL CLASSIFICATION:	REFUSE SYSTEMS [4953]
		ORGANIZATION NAME:           	01 Energy & Transportation
		IRS NUMBER:				030338873
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		25 GREENS HILL ROAD
		CITY:			RUTLAND
		STATE:			VT
		ZIP:			05701
		BUSINESS PHONE:		8027750325

	MAIL ADDRESS:	
		STREET 1:		25 GREENS HILL ROAD
		CITY:			RUTLAND
		STATE:			VT
		ZIP:			05701
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1731100980.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-11-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000911177</issuerCik>
        <issuerName>CASELLA WASTE SYSTEMS INC</issuerName>
        <issuerTradingSymbol>CWST</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001553453</rptOwnerCik>
            <rptOwnerName>Green Emily Nagle</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CASELLA WASTE SYSTEMS, INC.,</rptOwnerStreet1>
            <rptOwnerStreet2>25 GREENS HILL LANE</rptOwnerStreet2>
            <rptOwnerCity>RUTLAND</rptOwnerCity>
            <rptOwnerState>VT</rptOwnerState>
            <rptOwnerZipCode>05701</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-11-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>18729</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-11-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>745</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>105.14</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6763</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents a gift of shares to Lydia Green.</footnote>
        <footnote id="F2">Excludes 7,508 shares previously reported as directly owned by the reporting person but are now being reported as indirectly owned through the Jack Calvin Green Unelected Trust, of which the reporting person is a trustee and beneficiary.</footnote>
        <footnote id="F3">Reflects shares previously reported as directly owned by the reporting person but are now being reported as indirectly owned through the Jack Calvin Green Unelected Trust, of which the reporting person is a trustee and beneficiary.</footnote>
        <footnote id="F4">Shares held by the Jack Calvin Green Unelected Trust, of which the reporting person is a trustee and beneficiary.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Shelley E. Sayward, Attorney in Fact for Emily K. Nagle</signatureName>
        <signatureDate>2024-11-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
