<SEC-DOCUMENT>0001447669-22-000074.txt : 20220323
<SEC-HEADER>0001447669-22-000074.hdr.sgml : 20220323
<ACCEPTANCE-DATETIME>20220323200557
ACCESSION NUMBER:		0001447669-22-000074
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220321
FILED AS OF DATE:		20220323
DATE AS OF CHANGE:		20220323

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Wagner Dana
		CENTRAL INDEX KEY:			0001658462

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37806
		FILM NUMBER:		22764381

	MAIL ADDRESS:	
		STREET 1:		C/O TWILIO INC.
		STREET 2:		101 SPEAR STREET, FIRST FLOOR
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94105

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TWILIO INC
		CENTRAL INDEX KEY:			0001447669
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				262574840
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		101 SPEAR STREET
		STREET 2:		FIRST FLOOR
		CITY:			San Francisco
		STATE:			CA
		ZIP:			94105
		BUSINESS PHONE:		415-390-2337

	MAIL ADDRESS:	
		STREET 1:		101 SPEAR STREET
		STREET 2:		FIRST FLOOR
		CITY:			San Francisco
		STATE:			CA
		ZIP:			94105
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_164808034404146.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-03-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001447669</issuerCik>
        <issuerName>TWILIO INC</issuerName>
        <issuerTradingSymbol>TWLO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001658462</rptOwnerCik>
            <rptOwnerName>Wagner Dana</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O TWILIO INC.</rptOwnerStreet1>
            <rptOwnerStreet2>101 SPEAR STREET, FIRST FLOOR</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94105</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Legal Officer, Secretary</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-03-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>18761</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>82052</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The shares reported in this transaction represent RSUs. Each RSU represents the contingent right to receive one share of the Issuer's Class A common stock. The RSUs shall vest as follows: 33% of the RSUs shall vest in equal quarterly installments between the first and second anniversaries of January 1, 2022, 33% of the RSUs shall vest in equal quarterly installments between the second and third anniversaries of January 1, 2022, and 34% of the RSUs shall vest in equal quarterly installments between the third and fourth anniversaries of January 1, 2022, subject to the Reporting Person's continued employment with the Issuer through each vesting date.</footnote>
        <footnote id="F2">A portion of these shares represent RSUs. Each RSU represents a contingent right to receive one share of Issuer's Class A common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Judy Tieh as attorney in fact for Reporting Person</signatureName>
        <signatureDate>2022-03-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
