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): June 19, 2013

XENOPORT, INC.

(Exact name of registrant as specified in its charter)

Delaware

(State or other jurisdiction of incorporation)

3410 Central Expressway

Santa Clara, California 95051

(Address of principal executive offices) (Zip Code)

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

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 (see General Instruction A.2. below):

Section 7 – Regulation FD

Item 7.01 Regulation FD Disclosure.

On June 19, 2013, members of management of XenoPort, Inc. (“XenoPort,” or the “Company”) will meet with investors and analysts and present at the Wells Fargo Securities Research & Economics 2013 Healthcare Conference in Boston, Massachusetts. During these meetings and the presentation, the Company expects to provide an update to its financial guidance for 2013. The Company now expects its net use of cash for 2013 to be in the range of $85 million to $95 million (net use of cash is the difference between the anticipated balances of cash and cash equivalents plus short-term investments at December 31, 2013 and the actual of such balances at December 31, 2012). Further, the Company believes that its existing capital resources, together with the interest thereon, will be sufficient to meet its projected operating requirements into the third quarter of 2014.

The information in this Item 7.01 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, and it shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or under the Exchange Act, whether made before or after the date hereof, except as expressly set forth by specific reference in such filing to this item of this Current Report on Form 8-K.

This Current Report on Form 8-K contains “forward-looking” statements, including, without limitation, statements related to the Company’s expected net cash usage for 2013 and the timeframe during which the Company believes that its existing capital resources will be sufficient to meet its projected operating requirements. Any statements contained in this Current Report on Form 8-K that are not statements of historical fact may be deemed to be forward-looking statements. Words such as “anticipated,” “believes,” “expects,” “will” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon the Company’s current expectations. Forward-looking statements involve risks and uncertainties. The Company’s actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks related to XenoPort’s lack of commercialization experience and its ability to establish and maintain, or contract with third parties to establish and maintain, sufficient capabilities to manufacture and distribute Horizant^® (gabapentin enacarbil) Extended-Release Tablets; XenoPort’s ability to successfully market and sell Horizant, including its ability to obtain uninterrupted drug supply and appropriate pricing and reimbursement for Horizant in an increasingly challenging environment; XenoPort’s ability to comply with applicable regulatory guidelines and requirements with respect to the marketing and manufacturing of Horizant or with Horizant post-marketing commitments or requirements mandated by the U.S. Food and Drug Administration; XenoPort’s need for additional funding and the risk that XenoPort could utilize its available capital resources sooner than it expects; the uncertain results, costs and timing of clinical trials and other studies; and risks related to future opportunities and plans, including the uncertainty of expected future financial performance and results. The Company’s Quarterly Report on Form 10-Q, filed with the SEC on April 24, 2013, contains under the heading “Risk Factors,” a more comprehensive description of risks to which the Company is subject. The Company expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in the Company’s expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

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.