Justin is a city in Denton County, Texas, United States. The population was 1,891 at the 2005 census.
In 1848, approximately 70 followers of the French utopian socialist Etienne Cabet arrived in what is now Justin to found an Icarian community. The attempt failed.
Contrary to popular belief, the town is not named after or related to the Justin Boot Company. In January 1887 the community petitioned postal authorities for a post office to be named Justin, in honor of Justin Sherman, a chief engineer with the Santa Fe Railroad.