The Lone Star Ranger is a Western novel published by Zane Grey in 1915. The book takes place in Texas, the Lone Star State, and several main characters are Texas Rangers, a famous band of highly capable law enforcement officers. It follows the life of Buck Duane, a man who becomes an outlaw and then redeems himself in the eyes of the law.

The novel was dedicated to the Texas Ranger John Hughes.

Buck Duane is the son of a famous outlaw. Though an outlaw is not always a criminal, if the Rangers say he is an outlaw, it's just as bad – he's a hunted man. After killing a man in self-defense, Duane is forced to 'go on the dodge'. Duane turns up at an outlaw's hideout, still revolting at the idea of outlawry. Worse still, all the men he kills haunt him, for years. At the outlaw hideout, he meets a kidnapped, beautiful young woman and desires to see her free.

In the second part of the book, Duane joins the Rangers, who want him to help to clear the frontier of major cattle rustlers and bank robbers, in return for the governor's pardon of his illegal deeds.