Tillman County is a county located in the southwestern part of Oklahoma. As of the 2010 census, the population was 7,992. The county seat is Frederick.

The county was founded at the time of Oklahoma statehood in 1907, and was named for Senator Benjamin Tillman of South Carolina. It had previously been part of Comanche County, Oklahoma Territory. In 1910 and 1924 portions of Kiowa County were added to the north side of the county.