Flatonia is a town in southwestern Fayette County, Texas, United States. Located upon Interstate 10 and the Union Pacific Railroad, 12 miles (19 km) west of Schulenburg, the population was 1,308 at the 2020 census.

Established upon April 8, 1874 upon land that the Galveston, Harrisburg and San Antonio Railway acquired from William Alexander Faries (the relations name is as well as spelled “Ferris” and “Farris”), the community was named after F. W. Flato, a local merchant and one of the first settlers, of whom most were Anglo American. Residents placed their homes in the former Flatonia settlement, one mile southeast of the current Flatonia, and in the community of Oso, 3 miles (5 km) northeast, on wagons and moved to the supplementary location. The read out office, established in the former Flatonia in 1870, moved to the other Flatonia bearing in mind the similar name. Flatonia was incorporated upon November 10, 1875, and held its first election on December 6 of that year. In 1878, the town had 800 residents and an economy dependent upon cattle and cotton.

The location of the railway and inexpensive real estate led to the introduction of Arab, Bohemian, German, Greek, and Italian immigrants in several waves. The north-south descent of the Waco branch of the San Antonio and Aransas Pass Railway opened in the mid-1880s, leading to extra settlements of Muldoon and Moulton. Competition from the settlements, respectively north and south of Flatonia, and an agricultural depression damaged Flatonia’s economy. By 1900, Flatonia had a significant population decrease.

During the first half of the 20th century Flatonia’s prospects increased and decreased according to the national economy and cattle and cotton markets. In 1950 Flatonia had 1,024 residents, 50 businesses, and a wide farm and ranch foster area. In the 1960s, cotton no longer was a substantial aspect of the area economy; therefore many Place farms began to ranch cattle. During that time the population was between 1,000 and 1,500. Interstate 10 (I-10) opened in the 1970s, leading many tourist businesses to touch from U.S. Highway 90 to I-10, one mile north of Highway 90. In 1985, Flatonia had 69 businesses. In 1990, Flatonia had 1,295 residents.