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 13, 2016

XENOPORT, INC.

(Exact name of registrant as specified in its charter)

3410 Central Expressway

Santa Clara, California 95051

(Address of Principal Executive Offices) (Zip Code)

Registrant’s telephone number, including area code: (408) 616-7200

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:

Section 5—Corporate Governance and Management

Set forth below are the proposals voted upon at the Annual Meeting of Stockholders (the “Annual Meeting”) of XenoPort, Inc. (the “Company”) held on May 17, 2016 at the Santa Clara Marriott located at 2700 Mission College Blvd., Santa Clara, California, along with the final voting results thereon:

Proposal 1—To elect the two Class 2 directors named below to serve until the 2019 annual meeting of stockholders and until their successors have been duly elected and qualified. Each of the two named nominees was so elected, with the votes thereon at the Annual Meeting as follows:

Proposal 2— To ratify the selection by the audit committee of the board of directors of Ernst & Young LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2016. This proposal was approved by the requisite vote, with the votes thereon at the Annual Meeting as follows:

Proposal 3— To approve, on an advisory basis, the compensation of the Company’s named executive officers, as disclosed in the Company’s Proxy Statement for the Annual Meeting. This proposal was approved by the requisite vote, with the votes thereon at the Annual Meeting as follows:

Section 8—Other Events

The previously announced License, Development and Commercialization Agreement (the “Agreement”) between the Company and Dr. Reddy’s Laboratories, S.A. (“DRL”), executed on March 26, 2016, became effective on May 13, 2016, which triggered the $47.5 million upfront payment from DRL to the Company becoming due upon invoice under the Agreement. In addition, the Company delivered certain clinical trial materials to DRL to satisfy the condition for receipt of an additional $2.5 million payment from DRL. As previously announced, the effectiveness of the Agreement was subject to the parties receiving clearance under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”). On May 13, 2016, the waiting period under the HSR Act expired.

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.