Duel at Diablo is a 1966 western film starring James Garner in his first Western since leaving Maverick and Sidney Poitier in his first Western. Based on Marvin H. Albert's 1957 novel Apache Rising, the film was written by Albert and Michael M. Grilikhes and 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.