Flatonia is a town in southwestern Fayette County, Texas, United States. It is located on Interstate 10 and the Southern Pacific Railroad, twelve miles west of Schulenburg. The population was 1,377 at the 2000 census. It was incorporated in 1875 and is known for its German and Eastern European heritage and the local "Czhilispiel" festival; the festival, named after Czech people who like to eat chili, receives visitors from a large area in Central Texas.