Flat Creek Township is one of twenty-five townships in Barry County, Missouri, USA. As of the 2000 census, its population was 5,462.
Flat Creek Township covers an area of 53.31 square miles (138.1 km2) and contains one incorporated settlement, Cassville (the county seat). It contains six cemeteries: Corinth, Horner, Oak Hill, Pilant, Quaker and Russell.
Flat Creek Township contains one airport or landing strip, Cassville Municipal Airport.