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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2016-07-08</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001447028</issuerCik>
        <issuerName>Arbutus Biopharma Corp</issuerName>
        <issuerTradingSymbol>ABUS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001103804</rptOwnerCik>
            <rptOwnerName>VIKING GLOBAL INVESTORS LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001629482</rptOwnerCik>
            <rptOwnerName>Viking Global Opportunities Illiquid Investments Sub-Master LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001629472</rptOwnerCik>
            <rptOwnerName>Viking Global Opportunities Portfolio GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001629476</rptOwnerCik>
            <rptOwnerName>Viking Global Opportunities GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001133006</rptOwnerCik>
            <rptOwnerName>HALVORSEN OLE ANDREAS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001621842</rptOwnerCik>
            <rptOwnerName>Ott David C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001621588</rptOwnerCik>
            <rptOwnerName>Sundheim Daniel S.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>55 RAILROAD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>16013540</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Explanation of Responses</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The Reporting Persons (as defined below) do not directly own any shares of common stock (the &quot;Common Shares&quot;) of Arbutus Biopharma Corporation (the &quot;Issuer&quot;). The Reporting Persons acquired Roivant Sciences Ltd. (&quot;Roivant&quot;) common shares (the &quot;Roivant Common Shares&quot;) on December 8, 2015. Roivant directly holds the 16,013,540 Common Shares reported herein. Due to certain governance arrangements set forth in Roivant's bye-laws, as of the appointment of an independent director (within the meaning of that term under Roivant's bye-laws) to Roivant's board of directors effective July 8, 2016, the Reporting Persons may be deemed to have beneficial ownership over the Common Shares held by Roivant.</footnote>
        <footnote id="F2">O. Andreas Halvorsen, David C. Ott and Daniel S. Sundheim are Executive Committee members of certain management entities, including Viking Global Partners LLC, the general partner of Viking Global Investors LP (&quot;VGI&quot;), Viking Global Performance LLC (&quot;VGP&quot;), Viking Long Fund GP LLC (&quot;VLFGP&quot;) and Viking Global Opportunities GP LLC (&quot;Opportunities GP&quot;), the sole owner of Viking Global Opportunities Portfolio GP LLC (&quot;Opportunities Portfolio GP&quot;). VGI provides managerial services to various investment funds, including Viking Global Equities LP (&quot;VGE&quot;), Viking Global Equities II LP (&quot;VGE II&quot;), VGE III Portfolio Ltd. (&quot;VGE III&quot;), Viking Long Fund Master Ltd. (&quot;VLFM&quot;) and Viking Global Opportunities Illiquid Investments Sub-Master LP (&quot;Opportunities Fund&quot;, and together with VGE, VGE II, VGE III and VLFM, the &quot;Funds&quot; and the Funds together with VGI, VGP, VLFGP, Opportunities GP, Opportunities Portfolio GP, O. Andreas Halvorsen, David C. Ott and Daniel S. Sundheim, the &quot;Reporting Persons&quot;).</footnote>
        <footnote id="F3">VGP is the general partner of VGE and VGE II and the investment manager of VGE III. VLFGP serves as the investment manager of VLFM. Opportunities GP serves as the sole member of Opportunities Portfolio GP. Opportunities Portfolio GP serves as the general partner of Opportunities Fund.</footnote>
        <footnote id="F4">The Reporting Persons disclaim beneficial ownership of these securities except to the extent of their pecuniary interest therein, and the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of the reported securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the &quot;Exchange Act&quot;), or for any other purpose.</footnote>
    </footnotes>

    <remarks>(5) The Reporting Persons are jointly filing this Form 3 pursuant to Rule 16a-3(j) under the Exchange Act.

(6) Each of O. Andreas Halvorsen, David C. Ott and Daniel S. Sundheim is signing individually and as an Executive Committee Member of Viking Global Partners LLC, on behalf of VIKING GLOBAL INVESTORS LP, and as an Executive Committee Member of VIKING GLOBAL OPPORTUNITIES GP LLC, on behalf of itself and VIKING GLOBAL OPPORTUNITIES PORTFOLIO GP LLC and VIKING GLOBAL OPPORTUNITIES ILLIQUID INVESTMENTS SUB-MASTER LP.

(7) Because no more than 10 reporting persons can file any one Form 3 through the Securities and Exchange Commission's EDGAR system, VGP, VGE, VGE II, VGE III, VLFGP and VLFM have jointly filed with the Reporting Persons on a separate Form 3 filing submitted on the same day hereof.</remarks>

    <ownerSignature>
        <signatureName>/s/ O. Andreas Halvorsen (5)(6)</signatureName>
        <signatureDate>2016-07-13</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ David C. Ott (5)(6)</signatureName>
        <signatureDate>2016-07-13</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Daniel S. Sundheim (5)(6)</signatureName>
        <signatureDate>2016-07-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
