Frederick is a city and county seat of Tillman County, Oklahoma, United States. The population was 3,940 at the 2010 census. It is an agriculture-based community that primarily produces wheat, cotton, and cattle. Frederick is home to three dairies, a 1400-acre industrial park, and Frederick Regional Airport, which includes restored World War II hangars which house the World War II Airborne Demonstration Team.

Tillman County is a county located in the southwestern part of Oklahoma, United States. As of the 2020 census, the population was 6,968. The county seat is Frederick.