Guns for San Sebastian is a 1968 French Western film based on the 1962 novel A Wall for San Sebastian, written by Rev. Fr. William Barnaby "Barby" Faherty, S.J. The film is directed by Frenchman Henri Verneuil, and stars Anthony Quinn, Anjanette Comer and Charles Bronson. The score is by Ennio Morricone, who would then use his work in this film as an inspiration for the main theme in The Mercenary. Filming took place in Sierra de Órganos National Park in the town of Sombrerete, Mexico It was made as a co-production between France, Italy, and Mexico. It is a rare instance of a Spaghetti Western actually being shot in Mexico, instead of substituting Spain or some similar European location.

Henri Verneuil was a French-Armenian playwright and filmmaker, who made a successful career in France. He was nominated for Oscar and Palme d'Or awards, and won Locarno International Film Festival, Edgar Allan Poe Awards, French Legion of Honor, Golden Globe Award, French National Academy of Cinema and Honorary Cesar awards.