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): November 7, 2013

KiOR, INC.

(Exact name of registrant as specified in its charter)

13001 Bay Park Road, Pasadena, Texas 77507

(Address of principal executive offices, including zip code)

Registrant’s telephone number, including area code: (281) 694-8700

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:

Item 2.02 Results of Operations and Financial Condition.

On November 7, 2013, KiOR, Inc. (the “Company”) issued a press release announcing its financial results for the quarter ended September 30, 2013. A copy of the Company’s November 7, 2013 earnings press release is attached hereto as Exhibit 99.1.

The Company’s management will discuss these results on a conference call scheduled for today at 10:00 a.m. Eastern Time (9:00 a.m. Central Time). Participants may join the conference call by dialing (877) 468-8808 (for U.S. and Canada) or (443) 616-2702 (International). The conference access code is 33202210 for all participants. To listen via live webcast, please visit the investor relations section of the Company’s website: http://investor.kior.com/events.cfm. An audio replay of the conference call will remain available for seven days until Thursday, November 14, 2013 at 11:59 p.m. Eastern Time (10:59 p.m. Central Time) and can be accessed by dialing (855) 859-2056 (for U.S. and Canada) or (404) 537-3406 (International). The conference call replay access code is 33202210 for all participants. A replay of the webcast will also be available in the investors section of the Company’s website approximately two hours after the conclusion of the call and remain available for approximately 90 calendar days.

Pursuant to General Instruction B.2 of Form 8-K and Securities and Exchange Commission Release No. 33-8176, the information contained in the press release furnished as an exhibit hereto shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, is not subject to the liabilities of that section, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

The press release contains statements intended as “forward-looking statements,” all of which are subject to the cautionary statement about forward-looking statements set forth therein.

Item 7.01 Regulation FD Disclosure.

The information set forth in Item 2.02 above and in Exhibit 99.1 to this Current Report on Form 8-K is incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

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