Post Oak is an unincorporated community in Blanco County, in the U.S. state of Texas.

The area in what is known as Post Oak today was first settled by Pinkney Hickson circa 1874.

[2] Post Oak is located at the intersection of Farm to Market Roads 1320 and 2721 near Post Oak Creek, 8 mi (13 km) northwest of Johnson City in western Blanco County.

It joined the Johnson City Independent School District in the late 1930s.

[2] The community continues to be served by Johnson City ISD today.