UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-A

FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES

PURSUANT TO SECTION 12(b) OR 12(g) OF THE

SECURITIES EXCHANGE ACT OF 1934

Securities to be registered pursuant to Section 12(b) of the Act:

If this form relates to the registration of a class of securities pursuant to Section 12(b) of the Exchange Act and is effective pursuant to General Instruction A.(c), check the following box.   x

If this form relates to the registration of a class of securities pursuant to Section 12(g) of the Exchange Act and is effective pursuant to General Instruction A.(d), check the following box.   ¨

Securities Act registration statement file number to which this form relates (if applicable):

Securities to be registered pursuant to Section 12(g) of the Act:

None

(Title of Class)

EXPLANATORY NOTE

This Registration Statement on Form 8-A is being filed by Western Digital Corporation, a Delaware corporation (“we,” “us,” “our,” or the “Company”), in connection with the registration of the Company’s common stock, par value $0.01 per share (“Common Stock”), under Section 12(b) of the Securities Exchange Act of 1934, as amended, and the transfer of the listing of its Common Stock to the NASDAQ Global Select Market.

INFORMATION REQUIRED IN REGISTRATION STATEMENT

General

The Company’s authorized capital stock consists of 455,000,000 shares of Common Stock and 5,000,000 shares of preferred stock, par value $0.01 per share (“Preferred Stock”). No shares of Preferred Stock are issued or outstanding as of the date of filing of this Form 8-A.

The following is a summary of the material provisions of the Company’s Amended and Restated Certificate of Incorporation, as amended (our “Certificate of Incorporation”), and Amended and Restated Bylaws (our “Bylaws”), insofar as they relate to the material terms of our Common Stock. This summary is qualified in its entirety by reference to our Certificate of Incorporation and Bylaws, which are filed as Exhibits 3.1 and 3.2 hereto. Additionally, the General Corporation Law of the State of Delaware (the “DGCL”), may also affect the terms of our Common Stock.

Common Stock

Subject to the relative rights, limitations and preferences of the holders of any then outstanding Preferred Stock, holders of our Common Stock will be entitled to certain rights, including (i) to share ratably in dividends if, when and as declared by the Company’s Board of Directors (our “Board”) out of funds legally available therefor and (ii) in the event of liquidation, dissolution or winding up of the Company, to share ratably in the distribution of assets legally available therefor, after payment of debts and expenses. Each outstanding share of our Common Stock will entitle the holder to one vote on all matters submitted to a vote of the stockholders, including the election of directors, and the holders of shares of our Common Stock will possess the exclusive voting power. The holders of our Common Stock will not have cumulative voting rights in the election of directors or preemptive rights to subscribe for additional shares of our capital stock. Our Bylaws require that, in uncontested elections, each director be elected by the majority of votes cast with respect to such director. This means that the number of shares voted “for” a director nominee must exceed the number of votes cast “against” that nominee in order for that nominee to be elected.

Holders of shares of our Common Stock will have no preference, conversion, exchange, sinking fund, redemption or appraisal rights. The rights, preferences and privileges of holders of our Common Stock will be subject to the terms of any series of Preferred Stock which the Company may issue in the future.

Preferred Stock

Our Board has the authority, within the limitations and restrictions stated in our Certificate of Incorporation, to authorize the issuance of shares of Preferred Stock, in one or more classes or series, and to fix the rights, preferences, privileges and restrictions thereof, including dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, preemptive rights and the number of shares constituting any series or the designation of such series. The issuance of Preferred Stock could have the effect of decreasing the market price of our Common Stock and could adversely affect the voting and other rights of the holders of our Common Stock.

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Anti-Takeover Effect of Our Certificate of Incorporation and Bylaws and Delaware Law

Our Certificate of Incorporation and Bylaws include provisions, summarized below, that are intended to discourage and prevent coercive takeover practices and inadequate takeover bids. These provisions are designed to encourage persons seeking to acquire control of the Company to first negotiate with our Board. They are also intended to provide our management with the flexibility to enhance the likelihood of continuity and stability if our Board determines that a takeover is not in the best interests of our stockholders. These provisions, however, could have the effect of discouraging others from making tender offers for our shares and may have the effect of deterring hostile takeovers or delaying changes in our control or management.

Special Stockholder Meetings

Under our Bylaws, only our Board, the Chairman of the Board or our President may call special meetings of stockholders. Stockholders do not have the authority to call a special meeting of stockholders.

Requirements for Advance Notification of Stockholder Nominations and Proposals

Our stockholders must comply with advance notice procedures set forth in our Bylaws to bring business before or nominate directors for election at a meeting of stockholders.

Elimination of Stockholder Action by Written Consent

The DGCL permits stockholder action by written consent unless the corporation’s certificate of incorporation provides otherwise. Our Certificate of Incorporation eliminates the right of stockholders to act by written consent without a meeting.

No Cumulative Voting

Under Delaware law, cumulative voting for the election of directors is not permitted unless a corporation’s certificate of incorporation authorizes cumulative voting. Our Certificate of Incorporation and Bylaws do not provide for cumulative voting in the election of directors. The absence of cumulative voting makes it more difficult for a minority stockholder to gain a seat on our Board to influence our Board’s decision regarding a takeover.

Authorized but Unissued Shares

Subject to the requirements of The NASDAQ Stock Market LLC and other applicable law, our authorized but unissued shares of Common Stock may be available for future issuance without stockholder approval. We may use these additional shares for a variety of corporate purposes, including future public offerings to raise additional capital, corporate acquisitions and employee benefit plans. The existence of authorized but unissued shares of Common Stock could render more difficult or discourage an attempt to obtain control of us by means of a proxy contest, tender offer, merger or otherwise.

Undesignated Preferred Stock

The authorization of undesignated Preferred Stock makes it possible for our Board to issue Preferred Stock with voting or other rights or preferences that could impede the success of any attempt to change control of the Company.

Amendment of Provisions in Certificate of Incorporation and Bylaws

Our Certificate of Incorporation may be amended in accordance with Delaware law. Our Bylaws, or any of them, may be altered, amended or repealed, and new Bylaws may be adopted, (i) by our Board, by vote of a majority of the number of directors then in office as directors, acting at any duly called and held meeting of our Board, or (ii) by the stockholders, provided that notice of such proposed amendment, modification, repeal or adoption is given in the notice of special meeting.

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Delaware Anti-Takeover Law

We are subject to Section 203 of the DGCL, which is an anti-takeover law. In general, Section 203 prohibits a publicly-held Delaware corporation from engaging in a business combination with an interested stockholder for a period of three years following the date that the person became an interested stockholder, unless the business combination or the transaction in which the person became an interested stockholder is approved in a prescribed manner. Generally, a business combination includes a merger, asset or stock sale, or another transaction resulting in a financial benefit to the interested stockholder. Generally, an interested stockholder is a person who, together with affiliates and associates, owns 15% or more of the corporation’s voting stock. Under Section 203, a business combination between a corporation and an interested stockholder is prohibited unless it satisfies one of the following conditions:

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SIGNATURE

Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the Registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereto duly authorized.

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