Frank Boyd Gary (March 9, 1860 – December 7, 1922) was a United States senator from South Carolina.

He studied law, was admitted to the bar and commenced practice in Abbeville, South Carolina in 1881.

Gary was elected as a Democrat to the U.S. Senate to fill the vacancy caused by the death of Asbury C. Latimer and served from March 6, 1908, to March 4, 1909; he was not a candidate for reelection in 1908, and after his time in the Senate he was again a member of the State house of representatives in 1910.

Frank B. Gary was also appointed as special judge in Lexington County in the 1903 trial of James H. Tillman (lieutenant governor of South Carolina and nephew of Senator "Pitchfork" Ben Tillman) for the murder of N.G.

Gonzales had waged a virtual crusade against Tillman in the newspaper, helping ensure his defeat in the 1902 gubernatorial election.