Duel at Diablo is a 1966 American Western film starring James Garner in his first Western after leaving the long-running tv series Maverick, as well as Sidney Poitier in his first ever Western. Based on Marvin H. Albert's 1957 novel Apache Rising, the film was co-written by Albert and Michael M. Grilikhes; it was directed by Ralph Nelson, who had directed Poitier in Lilies of the Field. The supporting cast includes Bibi Andersson, Bill Travers, Dennis Weaver and John Hoyt; Ralph Nelson has a cameo as an Army Major. The movie was shot on location amidst striking scenery in southern Utah; the musical score was composed by Neal Hefti.