Trivia: Stanley Kubrick was very protective of Danny Lloyd, because he was so young. Through some careful and clever directing, Lloyd was unaware he was making a horror film until after the film's release.
Trivia: Kubrick tortured Shelly Duvall to get the performance he wanted out of her. He told the crew to have no sympathy for her, and pushed her to do many retakes until she would cry. The scene where she walked backwards on the stairs with the baseball bat was filmed up to 127 times by some counts. At the end of filming she presented Kubrick with clumps of her hair that had fallen out due to stress.
Trivia: Initially, the bathroom door Jack Nicholson was to axe in was an extremely thin one, made by the prop department to make it easier to destroy. However, Nicholson's technique with the axe was so good (he'd been a volunteer fire marshal) the door shattered into a million pieces, so they had to build a much stronger door to handle his swing.
Trivia: The famous scene where Wendy reads through Jack's accumulated work naturally doesn't have the same impact if the viewer can't read English. Therefore, for every foreign language the film was released in, Kubrick remade this shot with an appropriate cliche in each language - French, German, etc. Also, every page of every manuscript was hand-typed to recreate the realism of typos and misalignments.
Trivia: For the famous scene where Jack Nicholson breaks down the door with an axe, the crew made a fake door for him to break through, but had to replace it with a real door as the fake one broke too quickly due to Jack Nicholson's prior training as a fireman. This dates to his period of military service in the Air National Guard in 1957. After completing basic training at Lackland Air Force Base, Nicholson performed weekend drills and two-week annual training as a fire fighter assigned to the unit based at Van Nuys Airport. Some sources state they went through 60 doors during filming to get the footage Kubrick wanted.
Trivia: The infamous "Here's Johnny!" scene took three days to film.