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 3, 2020

BARRETT BUSINESS SERVICES, INC.

(Exact name of registrant as specified in charter)

Registrant’s telephone number, including area code: (360) 828-0700

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:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.     ¨

Item 2.02. Results of Operations and Financial Condition.

On November 3, 2020, Barrett Business Services, Inc. (the “Company”), issued a news release announcing its financial results for the third quarter ended September 30, 2020. The release also provides management’s forecast of diluted earnings per share for the 2020 full year, including related assumptions regarding gross billings and effective tax rate. A copy of the news release is furnished as Exhibit 99.1 to this report and incorporated by reference.

Item 7.01. Regulation FD Disclosure.

On November 3, 2020, the Company announced that its Board of Directors has declared a regular quarterly cash dividend of $0.30 per share. The dividend is payable on December 4, 2020, to all stockholders of record as of November 20, 2020.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits: The following exhibit is furnished with this Form 8-K:

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 thereunto duly authorized.