Form: 4

Statement of changes in beneficial ownership of securities

July 6, 2021

POWER OF ATTORNEY

Published on July 6, 2021

Exhibit 24

POWER OF ATTORNEY

The undersigned hereby constitutes and appoints each of Gary
Kramer, Anthony Harris, and Ben Ward, signing singly, the
undersigned's true and lawful attorney-in-fact to:

1. Execute for and on behalf of the undersigned, in
the undersigned's capacity as an officer and/or director of Barrett
Business Services, Inc. (the "Company"), Forms 3, 4, and 5 in
accordance with Section 16(a) of the Securities Exchange Act of 1934
and the rules thereunder, and any other forms or reports the
undersigned may be required to file in connection with the
undersigned's ownership, acquisition, or disposition of securities of
the Company, including forms required to generate codes for the
Securities and Exchange Commission's electronic filing system; and

2. Do and perform any and all acts for and on behalf
of the undersigned which may be necessary or desirable to complete
and execute any such Form 3, 4, or 5, or other form or report, and
timely file such form or report with the United States Securities and
Exchange Commission and any stock exchange or similar authority as
appropriate.

The undersigned hereby grants to each such attorney-in-fact
full power and authority to do and perform any and every act and
thing necessary or proper to be done in the exercise of any of the
rights and powers herein granted, as fully to all intents and
purposes as the undersigned could do if personally present, hereby
ratifying and confirming all that such attorney-in-fact shall
lawfully do or cause to be done by virtue of this power of attorney
and the rights and powers herein granted. The undersigned
acknowledges that the foregoing attorneys-in-fact, in serving in such
capacity at the request of the undersigned, are not assuming, and the
Company is not assuming, any of the undersigned's responsibilities to
comply with Section 16 of the Securities Exchange Act of 1934.

This Power of Attorney shall remain in full force and
effect until the undersigned is no longer subject to Section 16 of
the Securities Exchange Act of 1934 with respect to the undersigned's
holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing
delivered to the foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused this Power
of Attorney to be executed as of this 21st day of October, 2019.

/s/ Diane L. Dewbrey
Diane L. Dewbrey