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): July 30, 2014

KILROY REALTY CORPORATION

KILROY REALTY, L.P.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (310) 481-8400

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 Instructions A.2.):

On July 30, 2014, Kilroy Realty, L.P. (the “Operating Partnership”) and Kilroy Realty Corporation (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Wells Fargo Securities, LLC (“Wells Fargo Securities”), Barclays Capital Inc. (“Barclays”), Merrill Lynch, Pierce, Fenner & Smith Incorporated (“BofA Merrill Lynch”) and J.P. Morgan Securities LLC (“J.P. Morgan”).

Under the Underwriting Agreement, Wells Fargo Securities, Barclays, BofA Merrill Lynch and J.P. Morgan agreed to serve as representatives of the several underwriters listed on Schedule A attached to the Underwriting Agreement in connection with the public offering by the Operating Partnership of $400,000,000 aggregate principal amount of the Operating Partnership’s 4.25% Senior Notes due 2029. The notes will be guaranteed by the Company.

The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by the full text of the Underwriting Agreement, which is being filed as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated herein by reference.

On July 30, 2014, the Company issued a press release. A copy of the press release is furnished as Exhibit 99.1 to this report.

The information included in this Current Report on Form 8-K under this Item 7.01 (including Exhibit 99.1 hereto) is being “furnished” and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of Section 18, nor shall it be incorporated by reference into a filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such filing. The information included in this Current Report on Form 8-K under this Item 7.01 (including Exhibit 99.1 hereto) will not be deemed an admission as to the materiality of any information required to be disclosed solely to satisfy the requirements of Regulation FD.

(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.

Date: July 31, 2014

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.

Date: July 31, 2014

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EXHIBIT INDEX

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