John Coffee "Jack" Hays was an American military officer. A captain in the Texas Rangers and a military officer of the Republic of Texas, Hays served in several armed conflicts from 1836 to 1848, including against the Comanche Empire in Texas and during the Mexican–American War.

The Texas Ranger Division, also known as the Texas Rangers and also known as Diablos Tejanos, is an investigative law enforcement agency with statewide jurisdiction in the U.S. state of Texas. It is based in the capital city Austin. In the time since its creation, the Texas Rangers have investigated crimes ranging from murder to political corruption, acted in riot control and as detectives, protected the governor of Texas, tracked down fugitives, served as a security force at important state locations, including the Alamo, and functioned as a paramilitary force at the service of both the Republic (1836–1846) and the State of Texas.