UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

April 23, 2014 (April 22, 2014)

Date of Report (Date of Earliest Event Reported)

ALLERGAN, INC.

(Exact Name of Registrant as Specified in its Charter)

2525 Dupont Drive

Irvine, California 92612

(Address of Principal Executive Offices) (Zip Code)

(714) 246-4500

(Registrant’s Telephone Number, Including Area Code)

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

The information set forth under “Item 3.03 Material Modification to Rights of Security Holders” of this Current Report on Form 8-K with respect to the entry into a Rights Agreement is incorporated into this Item 1.01 by reference.

On April 22, 2014, the Board of Directors of Allergan, Inc. (the “Company”) adopted a Rights Agreement, dated as of April 22, 2014 between the Company and Wells Fargo Bank, N.A. as Rights Agent (as amended from time to time, the “Rights Agreement”). The Rights Agreement is not intended to prevent an acquisition of the Company on terms that the Board of Directors of the Company considers favorable to, and in the best interests of, all stockholders. Rather, the Rights Agreement aims to provide the Board of Directors of the Company with adequate time to fully assess any proposal. The description of the material terms and general effect of the Rights Agreement is set forth below.

In connection with the Rights Agreement, the Board of Directors of the Company declared a dividend of one preferred stock purchase right (the “Rights”) for each outstanding share of common stock, par value $0.01 per share (the “Common Stock”), of the Company outstanding at the close of business on May 8, 2014 (the “Record Date”). Each Right will entitle the registered holder thereof, after the Rights become exercisable and until 8:00 a.m. Eastern Time on April 22, 2015 (or the earlier redemption, exchange or termination of the Rights), to purchase from the Company one one-thousandth of a share of Series A Junior Participating Preferred Stock, par value $0.01 per share (the “Preferred Stock”), at a price of $500.00 per one one-thousandth of a share of Preferred Stock, subject to certain antidilution adjustments (the “Purchase Price”). Until the earlier to occur of (i) the close of business on the tenth business day following a public announcement that a person or group of affiliated or associated persons has acquired, or obtained the right to acquire, beneficial ownership of 10% or more of the Common Stock (including certain synthetic equity positions created by derivative securities) (an “Acquiring Person”) or (ii) the close of business on the tenth business day (or such later date as may be determined by action of the Board of Directors of the Company prior to such time as any person or group of affiliated persons becomes an Acquiring Person) following the commencement or announcement of an intention to make a tender offer or exchange offer the consummation of which would result in any person becoming an Acquiring Person (the earlier of (i) and (ii) being called the “Distribution Date”), the Rights will be evidenced, with respect to any Common Stock certificates outstanding as of the Record Date, by such Common Stock certificates, or, with respect to any uncertificated shares of Common Stock registered in book entry form outstanding as of the Record Date, by notation in book entry.

The Rights Agreement provides that any person who beneficially owned 10% or more of the Common Stock immediately prior to the first public announcement of the Rights Agreement, together with any affiliates and associates of that person (each an “Existing Holder”), shall not be deemed to be an “Acquiring Person” for purposes of the Rights Agreement unless the Existing Holder becomes the beneficial owner of one or more additional shares of Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding Common Stock in Common Stock or pursuant to a split or subdivision of the Common Stock). However, if upon acquiring beneficial ownership of one or more additional shares of Common Stock, the Existing Holder does not beneficially own 10% or more of the Common Stock of the Company then outstanding, the Existing Holder shall not be deemed to be an “Acquiring Person” for purposes of the Rights Agreement.

The Rights will be transferred only with the Common Stock until the Distribution Date or earlier redemption or expiration of the Rights. As soon as practicable following the Distribution Date, separate certificates evidencing the Rights (“Right Certificates”) will be mailed to holders of record of the Common Stock as of the close of business on the Distribution Date and such separate Right Certificates alone will evidence the Rights. The Rights will at no time have any voting rights.

Each share of Preferred Stock purchasable upon exercise of the Rights will be entitled, when, as and if declared, to a minimum preferential quarterly dividend payment of $1.00 per share or, if greater, an aggregate dividend equal to 1,000 times the dividend, if any, declared per share of Common Stock. In the event of liquidation, dissolution or winding up of the Company, the holders of the Preferred Stock will be entitled to a preferential liquidation payment equal to $1,000 per share plus any accrued but unpaid dividends, provided that the holders of the Preferred Stock shall be entitled to 1,000 times the payment made per share of Common Stock. Each share of Preferred Stock will have 1,000 votes and will vote together with the Common Stock. Finally, in the event of any merger, consolidation or other transaction in which the Common Stock is exchanged, each share of Preferred Stock will be entitled to receive 1,000 times the amount received per share of Common Stock. The Preferred Stock will not be redeemable. The Rights are protected by customary anti-dilution provisions. Because of the nature of the Preferred Stock’s dividend, liquidation and voting rights, the value of one one-thousandth of a share of Preferred Stock purchasable upon exercise of each Right should approximate the value of one share of Common Stock.

In the event that a person becomes an Acquiring Person or if the Company were the surviving corporation in a merger with an Acquiring Person or any affiliate or associate of an Acquiring Person and the shares of Common Stock were not changed or exchanged, each holder of a Right, other than Rights that are or were acquired or beneficially owned by the Acquiring Person (which Rights will thereafter be void), will thereafter have the right to receive upon exercise that number of shares of Common Stock having a market value of two times the then current Purchase Price of one Right. In the event that, after a person has become an Acquiring Person, the Company were acquired in a merger or other business combination transaction or more than 50% of its assets or earning power were sold, proper provision shall be made so that each holder of a Right shall thereafter have the right to receive, upon the exercise thereof at the then current Purchase Price of the Right, that number of shares of common stock of the acquiring company which at the time of such transaction would have a market value of two times the then current Purchase Price of one Right.

At any time after a person becomes an Acquiring Person and prior to the earlier of one of the events described in the last sentence in the previous paragraph or the acquisition by such Acquiring Person of 50% or more of the then outstanding Common Stock, the Board of Directors may cause the Company to exchange the Rights (other than Rights owned by an Acquiring Person which have become void), in whole or in part, for shares of Common Stock at an exchange rate of one share of Common Stock per Right (subject to adjustment).

The Rights may be redeemed in whole, but not in part, at a price of $0.01 per Right (the “Redemption Price”) by the Board of Directors at any time prior to the time that an Acquiring Person has become such. The redemption of the Rights may be made effective at such time, on such basis and with such conditions as the Board of Directors in its sole discretion may establish. Immediately upon any redemption of the Rights, the right to exercise the Rights will terminate and the only right of the holders of Rights will be to receive the Redemption Price.

The Rights will expire at 8:00 a.m. Eastern Time on April 22, 2015 (unless earlier redeemed, exchanged or terminated).

The Purchase Price payable, and the number of one one-thousandth of a share of Preferred Stock or other securities or property issuable, upon exercise of the Rights are subject to adjustment from time to time (i) in the event of a stock dividend on, or a subdivision, combination or reclassification of, the Preferred Stock, (ii) upon the grant to holders of the Preferred Stock of certain rights, options or warrants to subscribe for or purchase Preferred Stock or convertible securities at less than the current market price of the Preferred Stock or (iii) upon the distribution to holders of the Preferred Stock of evidences of indebtedness, cash, securities or assets (excluding regular periodic cash dividends at a rate not in excess of 125% of the rate of the last regular periodic cash dividend theretofore paid or, in case regular periodic

cash dividends have not theretofore been paid, at a rate not in excess of 50% of the average net income per share of the Company for the four quarters ended immediately prior to the payment of such dividend, or dividends payable in shares of Preferred Stock (which dividends will be subject to the adjustment described in clause (i) above)) or of subscription rights or warrants (other than those referred to above).

Until a Right is exercised, the holder thereof, as such, will have no rights as a shareholder of the Company beyond those as an existing shareholder, including, without limitation, the right to vote or to receive dividends.

Any of the provisions of the Rights Agreement may be amended by the Board of Directors of the Company, or a duly authorized committee thereof, for so long as the Rights are then redeemable, and after the Rights are no longer redeemable, the Company may amend or supplement the Rights Agreement in any manner that does not adversely affect the interests of the holders of the Rights.

One Right will be distributed to shareholders of the Company for each share of Common Stock owned of record by them on May 8, 2014. As long as the Rights are attached to the Common Stock, the Company will issue one Right with each new share of Common Stock so that all such shares will have attached Rights. The Company has agreed that, from and after the Distribution Date, the Company will reserve 400,000 shares of Preferred Stock initially for issuance upon exercise of the Rights.

The Rights may also have the effect of assuring that all of the Company’s shareholders receive fair and equal treatment in the event of any proposed takeover of the Company and to guard against partial tender offers, open market accumulations and other abusive or coercive tactics to gain control of the Company without paying all shareholders a control premium. The Rights will cause substantial dilution to a person or group that acquires 10% or more of the Company’s stock on terms not approved by the Company’s Board of Directors. The Rights should not interfere with any merger or other business combination approved by the Board of Directors at any time prior to the first date that a person or group has become an Acquiring Person.

The Rights Agreement specifying the terms of the Rights and the text of the press release announcing the declaration of the Rights are incorporated herein by reference as exhibits to this current report. The foregoing description of the Rights is qualified in its entirety by reference to such exhibits.

To the extent applicable, the information set forth under “Item 3.03 Material Modification to Rights of Security Holders” of this Current Report on Form 8-K with respect to the Certificate of Designations of Series A Junior Participating Preferred Stock is incorporated into this Item 5.03 by reference.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit Index