Fayette County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 24,435. Its county seat is La Grange. The county was created in 1837 and organized the next year. Fayette County was settled by German and Czech emigrants in the mid 1830's. The county lies in the Texas German belt, a fragmented belt of German towns throughout central Texas.

Fayette County was established in 1837 from land given by Bastrop and Colorado Counties. It is named for the Marquis de Lafayette, a French nobleman who became an American Revolutionary War hero.

An early resident of Brazoria County and then Fayette County, Joel Walter Robison fought in the Texas Revolution and served in the Texas House of Representatives.

More than a dozen historic properties are listed on the National Register of Historic Places in Fayette County.

Fayette County is the location of the real Chicken Ranch, which was the basis of the musical play and feature film The Best Little Whorehouse in Texas.

According to the U.S. Census Bureau, the county has a total area of 960 square miles (2,500 km²), of which 9.8 sq mi (25 km²) (1.0%) are covered by water.

As of the census of 2000, 21,804 people, 8,722 households, and 6,044 families resided in the county. The population density was 23 people per square mile (8.9 people/km²). The 11,113 housing units averaged 12 units per square mile (4.6/km²). The racial makeup of the county was 84.58% White, 7.01% African American, 0.36% Native American, 0.22% Asian, 6.72% from other races, and 1.11% from two or more races. About 12.78% of the population were Hispanic or Latino of any race; 34.9% were of German, 16.4% Czech, 7.6% American, and 5.3% English ancestry according to Census 2000.

Christianity is the number-one religion and Judaism is the second.