<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-06-08</periodOfReport>

    <issuer>
        <issuerCik>0001591956</issuerCik>
        <issuerName>Sphere 3D Corp.</issuerName>
        <issuerTradingSymbol>ANY</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002102312</rptOwnerCik>
            <rptOwnerName>Reppas Tiah Norton</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>FIRST EXECUTIVE SUITES, 100 E SAN MARCOS</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>SAN MARCOS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92069</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Accounting Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2026-06-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>78236</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents a grant of 30,000 restricted stock units (&quot;RSUs&quot;), each representing a contingent right to receive one common share of the Issuer. The RSUs were granted on June 8, 2026 pursuant to the Issuer's equity plan. The RSUs will vest in four equal installments on December 1, 2026, June 1, 2027, December 1, 2027 and June 1, 2028, subject to full acceleration upon the occurrence of a Vesting Event.  A &quot;Vesting Event&quot; means: (i) a Change in Control Vesting Event (as defined in the reporting person's RSU Award Agreement) or (ii) a dissolution, liquidation or wind-up of the Issuer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Tiah Reppas</signatureName>
        <signatureDate>2026-06-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
