Thomas Kilby Smith (September 23, 1820 – December 14, 1887) was a lawyer, soldier, and diplomat from the state of Ohio who served as a general in the Union Army during the American Civil War and then in the postbellum United States Army.
He led a brigade and then a division in the Army of the Tennessee in several of the most significant campaigns of the Western Theater of operations before failing health forced him to a series of desk jobs.