Gen. Mapache's headquarters, where the climatic shootout takes place between the Wild Bunch and Mapache's soldiers, was actually an abandoned winery outside the town of Parras in Coahuila, Mexico. The shootout that opened the film, which was when the Wild Bunch was ambushed by bounty hunters while robbing the railroad office in the Texas town of Starbuck, was actually shot on the Main Street of downtown Parras.
In 2007, the American Film Institute ranked this as the #79 Greatest Movie of All Time.
In an interview, Ben Johnson said that the two Mexican women who "frolicked" with him and Warren Oates in the huge wine vats weren't actresses but prostitutes from a nearby brothel, who were hired by Sam Peckinpah so he could tell people that Warner Bros. paid for hookers for his cast.
Last scene to be completed was the exploding bridge over Rio Nazas (substituting for Rio Bravo). Five stuntmen, each paid $2,000, one take, six cameras. One camera was lost into the water.
Pike Bishop may have been named after Bishop James Albert Pike, a leader in California's Episcopal Church known for his outspoken support of progressive causes.
Ranked #6 on the American Film Institute's list of the 10 greatest films in the genre "Western" in June 2008.
Seven identical costumes were made for each main actor. All of them were ruined during filming.
Supposedly, more blank rounds were discharged during the production than live rounds were fired during the Mexican Revolution of 1913 around which the film is loosely based. In total 90,000 rounds were fired, all blanks.
The "modern" sidearms (the film's setting is 1913) that the Bishop gang carries are Colt M1911 automatic pistols and Winchester M1897 pump-action shotguns. The water-cooled heavy machine gun is the Browning M1917. US and Mexican soldiers use M1903 Springfield rifles. All of the aforementioned weapons were used in World War I by the US Army.
While the 1897 Winchester shotgun was featured prominently, they were not used exclusively by the Bunch. The shotgun that Crazy Lee had at the start of the movie in the railroad office, did not have an exposed hammer, which is something all 1987s have. Neither the 1897 or the Winchester Model 12 had a trigger disconnector, which means the trigger could be continually depressed and every time the the slide was pumped it would fire. Since this was what we see the Bunch doing as they are firing through the railroad office windows at the bounty hunters on the roof, at least the shotgun that Crazy Lee loaned briefly to Abe must have been a M12, based on it not having an exposed hammer. This can be see most clearly when Crazy Lee is firing at the 3 people he was holding in the office, after they tried to escape.
The budget went from $3.5 to $6 million and from 70 to 81 shooting days.
The climatic gun battle sequence took 12 days to film. The crew nicknamed it the "Battle of Bloody Porch."
The famous "Last Walk" was improvised by Sam Peckinpah during the shoot. Originally, the scene was to begin with the Bunch leaving the whorehouse and immediately cut to the confrontation with Mapache. Once the decision was made to lengthen the scene, many of the Mexican extras were choreographed by the assistant directors while the scene was filming.
The image of the scorpion being dropped in the ant hill was suggested by Emilio Fernández because he and his friends used to do that as children. The image was not in the script.
The movie's line "If they move, kill 'em." was voted as the #72 of "The 100 Greatest Movie Lines" by Premiere in 2007.
The name "The Wild Bunch" originally came from real-life western outlaw Butch Cassidy. At age 30 he started his own gang of outlaws, who were quickly christened "The Wild Bunch" by the press.
The role of Gen. Mapache was first offered to the German-Italian actor Mario Adorf. Adorf declined the offer when he learned that his character would cut a boy's throat, but regretted his decision three years later when he saw the movie.
The shootout/massacre in the end took 12 days to film. When completed, about 10,000 squibs (simulated bullet hits) had been used.
The song "Polly Wolly Doodle" was prominently featured in Frank Capra's You Can't Take It with You, where Dub Taylor (Rev. Wainscoat in the "Wild Bunch") plays the song (several times) on a xylophone. "You Can't Take It With You" marked the beginning of Taylor's film career. Sam Peckinpah's "Polly Wolly Doodle", presented in its sinister context, contrasts sharply with the carefree Capra rendition.
The train robbery itself was not in the script. All scenes were improvised on the spot, the same day. Same thing with "the walk" for the bunch to help "Angel".