Hour of the Gun is a 1967 Western film depicting Wyatt Earp and Doc Holliday during their 1881 battles against Ike Clanton and his brothers in the Gunfight at the O.K. Corral, and the gunfight's aftermath in and around Tombstone, Arizona, starring James Garner as Earp, Jason Robards as Holliday, and Robert Ryan as Clanton. The film was directed by John Sturges.

Sturges had previously directed a highly fictionalized version of the same events in the film Gunfight at the O.K. Corral (1957) starring Burt Lancaster and Kirk Douglas, but in Hour of the Gun he strove for more historical accuracy than in most previous screen depictions of Earp's adventures. The film is based on the non-fiction book Tombstone's Epitaph by Douglas D. Martin, with a screenplay by Edward Anhalt.

During the film's opening title and credits sequence, an onscreen title appears last: "This picture is based on Fact. This is the way it happened." Hour of the Gun is in fact more accurate than its predecessors in many ways. For instance, it correctly shows Ike Clanton surviving the O.K. Corral shoot-out, whereas previous films had shown him being one of its fatalities.

However, not everything in the film hews strictly to fact. It has Ike Clanton ultimately being killed by Wyatt Earp, whereas Clanton actually died in an 1887 duel with a constable named Jonas Brighton. In addition, Hour of the Gun portrays Doc Holliday as a graying Civil War veteran much older than the Earp brothers, though in fact he was younger than most of them and was too young to have served in that conflict. The death of Curly Bill Brocious is inaccurately portrayed as a street shootout between Brocius and two others vs. Wyatt Earp and Doc Holliday. Furthermore, the opening depicts the gunfight as happening at the OK Corral, whereas it actually happened at a nearby photography studio.