Heritage Financial (HFWA) 10-Q 2011 Q2 Quarterly report

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Heritage Financial Corporation (the “Company”) on Form 10-Q for the quarter ended June 30, 2011 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), we, Brian L. Vance, President and Chief Executive Officer and Donald J. Hinson, Senior Vice President and Chief Financial Officer of the Company, certify in our capacity as an officer of the Company, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company as of the dates and for the periods presented in the financial statements included in such Report.

August 4, 2011

/s/    Brian L. Vance

Brian L. Vance

President and Chief Executive Officer

Principal Executive Officer

/s/    Donald J. Hinson

Donald J. Hinson

Senior Vice President and Chief Financial Officer

Principal Financial Officer