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

Date of Report (Date of earliest event reported): May 15, 2015

Plains All American Pipeline, L.P.

(Exact name of registrant as specified in its charter)

333 Clay Street, Suite 1600, Houston, Texas 77002

(Address of principal executive offices) (Zip Code)

713-646-4100

(Registrant’s telephone number, including area code)

(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:

o                                    Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o                                    Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o                                    Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o                                    Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 5.03.                                        Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On and effective as of May 15, 2015, the general partner of Plains All American Pipeline, L.P. (the “Partnership”) executed Amendment No. 3 (the “Amendment”) to the Partnership’s Fourth Amended and Restated Agreement of Limited Partnership (the “Partnership Agreement”).

The Amendment amends and restates Section 16.8 of the Partnership Agreement to provide that the Court of Chancery of the State of Delaware (or, if such court does not have subject matter jurisdiction thereof, any other court located in the State of Delaware with subject matter jurisdiction) shall be the sole and exclusive forum for claims, suits, actions or proceedings: (i) arising out of or relating in any way to the Partnership Agreement; (ii) brought in a derivative manner on behalf of the Partnership; (iii) asserting a claim of breach of a fiduciary duty owed by any director, officer, or other employee of the Partnership or its general partner, or owed by its general partner, to the Partnership or the partners; (iv) asserting a claim arising pursuant to any provision of the Delaware Revised Uniform Limited Partnership Act; or (v) asserting a claim governed by the internal affairs doctrine.

The foregoing description of the Amendment is qualified in its entirety by reference to the text of the Amendment, which is filed as Exhibit 3.1 hereto and is incorporated herein by reference.

Item 9.01.                                        Financial Statements and Exhibits.

(d) Exhibits

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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.

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EXHIBIT INDEX

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Exhibit 3.1

AMENDMENT NO. 3 TO THE FOURTH AMENDED AND RESTATED

AGREEMENT OF LIMITED PARTNERSHIP OF

PLAINS ALL AMERICAN PIPELINE, L.P.

This Amendment No. 3 (this “Amendment”) to the Fourth Amended and Restated Agreement of Limited Partnership of Plains All American Pipeline, L.P., a Delaware limited partnership (the “Partnership”), dated as of May 17, 2012 (and as amended to the date hereof, the “Partnership Agreement”), is hereby adopted effective as of May 15, 2015, by PAA GP LLC, a Delaware limited liability company (the “General Partner”), as general partner of the Partnership.  Capitalized terms used but not defined herein are used as defined in the Partnership Agreement.

WHEREAS, Section 13.1(d)(i) of the Partnership Agreement provides that the General Partner, without the approval of any Partner, may amend any provision of the Partnership Agreement to reflect a change that, in the discretion of the General Partner, does not adversely affect the Limited Partners in any material respect;

WHEREAS, the General Partner has determined, in its discretion, that this Amendment does not adversely affect the Limited Partners in any material respect;

NOW, THEREFORE, the General Partner does hereby amend the Partnership Agreement as follows:

Section 1.  Section 16.8 of the Partnership Agreement is hereby amended and restated in its entirety as follows:

Section 16.8                             Applicable Law; Forum; Venue and Jurisdiction.

(a)                                 This Agreement shall be construed in accordance with and governed by the laws of the State of Delaware, without regard to the principles of conflicts of law.

(b)                                 Each of the Partners and each Person holding any beneficial interest in the Partnership (whether through a broker, dealer, bank, trust company or clearing corporation or an agent of any of the foregoing or otherwise):

(i)                                     irrevocably agrees that any claims, suits, actions or proceedings (A) arising out of or relating in any way to this Agreement (including any claims, suits or actions to interpret, apply or enforce the provisions of this Agreement or the duties, obligations or liabilities among Partners or of Partners to the Partnership, or the rights or powers of, or restrictions on, the Partners or the Partnership), (B) brought in a derivative manner on behalf of the Partnership, (C) asserting a claim of breach of a fiduciary duty owed by any director, officer, or other employee of the Partnership or the General Partner, or owed by the General Partner, to the Partnership or the Partners, (D) asserting a claim arising pursuant to any provision of the Delaware Act or (E) asserting a claim governed by the internal affairs doctrine shall be exclusively brought in the Court of Chancery of the State of Delaware (or, if such court does not have subject matter jurisdiction thereof, any other court located in the State of Delaware with subject matter jurisdiction), in each case regardless of whether such claims, suits, actions or

proceedings sound in contract, tort, fraud or otherwise, are based on common law, statutory, equitable, legal or other grounds, or are derivative or direct claims;

(ii)                                  irrevocably submits to the exclusive jurisdiction of the Court of Chancery of the State of Delaware (or, if such court does not have subject matter jurisdiction thereof, any other court located in the State of Delaware with subject matter jurisdiction) in connection with any such claim, suit, action or proceeding;

(iii)                               agrees not to, and waives any right to, assert in any such claim, suit, action or proceeding that (A) it is not personally subject to the jurisdiction of the Court of Chancery of the State of Delaware or of any other court to which proceedings in the Court of Chancery of the State of Delaware may be appealed, (B) such claim, suit, action or proceeding is brought in an inconvenient forum, or (C) the venue of such claim, suit, action or proceeding is improper;

(iv)                              expressly waives any requirement for the posting of a bond by a party bringing such claim, suit, action or proceeding; and

(v)                                 consents to process being served in any such claim, suit, action or proceeding by mailing, certified mail, return receipt requested, a copy thereof to such party at the address in effect for notices hereunder, and agrees that such services shall constitute good and sufficient service of process and notice thereof; provided, nothing in clause (v) hereof shall affect or limit any right to serve process in any other manner permitted by law.

Section 3.  Except as hereby amended, the Partnership Agreement shall remain in full force and effect.

Section 4.  This Amendment shall be governed by, and interpreted in accordance with, the laws of the State of Delaware, all rights and remedies being governed by such laws without regard to principles of conflicts of laws.

Section 5.  If any provision of this Amendment is or becomes invalid, illegal or unenforceable in any respect, the validity, legality and enforceability of the remaining provisions contained herein shall not be effected thereby.

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IN WITNESS WHEREOF, this Amendment has been executed as of the date first written above.

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