Texline is a town in northwestern Dallam County, Texas, United States. The population was 507 at the 2010 Census. The town is named for its location near the New Mexico-Texas state line. The town sits on U.S. Highway 87, which continues southeast towards Dalhart and northwest towards Clayton, New Mexico.

Dallam County is the north-westernmost county in the U.S. state of Texas. As of the 2020 Census, its population was 7,115. Its county seat is Dalhart. The county was founded in 1876 and later organized in 1891. It is named for James Wilmer Dallam, a lawyer and newspaper publisher.