Exhibit 21

SUBSIDIARIES OF THE REGISTRANT

S&T Bancorp, Inc., a Pennsylvania corporation, is a financial holding company. The table below sets forth all of our subsidiaries, except certain inactive subsidiaries, as to state or jurisdiction of organization. 

Subsidiary	State or Jurisdiction of Organization
S&T Bank	Pennsylvania
9th Street Holdings, Inc.	Delaware
S&T Bancholdings, Inc.	Delaware
S&T Insurance Group, LLC	Pennsylvania
S&T Professional Resources Group, LLC	Pennsylvania
S&T-Evergreen Insurance, LLC (sold 1/1/2018)	Pennsylvania
S&T Settlement Services, LLC	Pennsylvania
Stewart Capital Advisors, LLC	Pennsylvania
STBA Capital Trust I	Delaware
Commonwealth Trust Credit Life Insurance Company	Arizona
DNB Capital Trust I	Delaware
DNB Capital Trust II	Delaware
DNB Financial Services, Inc.	Pennsylvania
Downco, Inc.	Pennsylvania
DN Acquisition Company, Inc.	Pennsylvania