La Coste is a city in Medina County, Texas, United States.

According to the United States Census Bureau, the city has a total area of 0.6 square miles (1.6 km2), all of it land.

As of the 2020 United States census, there were 1,077 people, 632 households, and 500 families residing in the city.

16.6% of all households were made up of individuals, and 6.7% had someone living alone who was 65 years of age or older.

The City of La Coste is served by the Medina Valley Independent School District.