Although in the film the main characters get on well, the actors who played the Scarecrow, the Tinman and the Lion actually resented Judy Garland as they were convinced that she was trying to up-stage them. This wasn't true, but Garland had a very hard time when making the film as she was only friendly with Margaret Hamilton and her musical director, Roger Edens. Actually at the time, Garland was on a much lower salary than most of the stars. She received $500 a month, with $200 of that for her mother Ethel's services.

The original head of Oz that appeared in front of the columns was a fake robotic head that the producers later replaced with a real actor's head.

Originally, the Wicked Witch of the West recorded a lot more scenes. Most of these scenes were cut because the director thought it would scare the children too much. You can see evidence of this when the foursome are surrounded by her guards and the witch comes and says something like Ring around the Rosie and it cuts to a different scene with her in it.

The steam shooting from the Tin Man's cap startles Toto, who runs out of the shot.

In the original book by L. Frank Baum, Dorothy's slippers were not Ruby but Silver. The color was changed in the movie for technicolor purposes.

Buddy Ebsen was originally slated to play the Scarecrow, with Ray Bolger originally the Tin Woodman; Bolger asked to switch places since his dancing style was much closer to how a scarecrow would dance than to a tin woodsman.

Contrary to common belief, "The Wizard of Oz" is not based on Populism (a mostly rural movement in the 1890s that challenged the interests of the railroads and big business) and its ideals. This myth originated from the fact that writer L. Frank Baum had been the editor of a Populist newspaper in Kansas prior to writing the Oz books.

Gale Sondergaard didn't want to play the Witch of the West because she thought the make-up made her look ugly.

The album "Dark side of the moon" by Pink Floyd seems to be in sync (by accident or design) with the Wizard of Oz if you start it right after the MGM lion roars the third time. Examples: the smoke turns black and blue when they are visiting the wizard as the words "black and blue" are sung. When the tone of the movie changes as Dorothy falls in the pigpen, the music picks up, becoming somewhat "panicky." When Auntie Em is "gripping" at the Uncles, the music has a nagging woman's voice that matches Auntie Em perfectly. The Tin Man's dance to a track called Speak to Me/Breathe. This has to be done with DVD/CD, and bear in mind that PAL format DVDs play back 4% faster due to differing frame rates, so for a 101 minute film like this it'll be 4 minutes apart from the NTSC version by the end, potentially messing up any synchronisation.

Shirley Temple was going to play Dorothy but no one knows the real whole story of why she was turned down. MGM's side of the story is that her voice wasn't good enough, but FOX's side of the story is that Jean Harlow and Clark Gable were going to come work at FOX so she could work at MGM, but after Harlow's death (from uremic poisoning brought on by acute nephritis) in 1937 the deal was over. It could have been one way or the other or also both ways. They possibly could have not told the real story to Temple's mother to not hurt the actress' feelings.