Continuity mistake: When they first meet Tin Man he is holding plants in his left hand. They change each time we see them. (00:41:15)
Revealing mistake: The Scarecrow tells Dorothy to, "just bend the nail down in the back and maybe I'll slip off" but what she actually does is pull a lever. (00:35:40)
Suggested correction: I have the scene up right now, and the nail on the pole just looks like... a huge nail. Then Dorothy bends it, and the Scarecrow falls off. I'm not denying that it's a lever, because it's entirely possible that it is. The thing is, there is nothing in the scene that indicates that it absolutely has to be a lever, and it can't be a nail at all.
Continuity mistake: Back in Kansas, Dorothy holds Toto and her pigtails swap from being behind to in front.
Continuity mistake: As they stand in the Wizard's balloon, Toto is looking at the Cowardly Lion. In the next shot he's growling at a cat. (01:34:45)
Continuity mistake: As she watches the Wicked Witch "melt", Dorothy and the others stand about five feet to the left of the Wicked Witch. They never move but when she asks for the broomstick she's standing right above her "melted" remains. (01:26:50)
Continuity mistake: The Tin Man holds on to the Lion's tail as he reaches the top of the mountain. In the next shot he says, "I hope my strength holds out" and he's back on the side of the mountain. (01:20:00)
Continuity mistake: Dorothy faces the Munchkins as they sing, "We welcome you to Munchkinland". In the next shot she's facing the Mayor. (00:28:30)
Continuity mistake: In the beginning of the movie Dorothy comes running into the farm and starts to, but doesn't completely unfasten the strap around her books. In the next shot the strap is in her hand. (00:02:20)
Continuity mistake: As he escapes Toto runs up the drawbridge and moves a foot to the left between shots than back again. (01:17:30)
Continuity mistake: When they first meet the Tin Man, the Scarecrow is holding an apple in each hand. He drops the one in his right hand but the other one disappears when he reaches for the oil can. Later when they all walk away both apples, and the one that Dorothy dropped before, are gone. (00:44:05)
Continuity mistake: The Munchkin Mayor's watch keeps changing time, from nearly to the hour, to twenty after the hour.
Continuity mistake: When we first meet the three farmhands Hunk is leaning on the wagon's break pad. In the next shot he's not. (00:03:05)
Continuity mistake: At the end of the movie, when Dorothy sits up, from the side shot her hair is shown going down her back, but in the front shot, her hair is in the front.
Continuity mistake: When the companions are walking down the corridor to the wizard's room, Toto is on their left side. Then, the camera view suddenly cuts to being behind them, and in which case, Toto is suddenly on their right side.
Revealing mistake: In the Haunted Forest, when the Tin Man is lifted up then lands back on the ground, at Tin Man's lower back you can see his white T-shirt tucked into his pants. (01:14:10)
Audio problem: As they all stand at the door to Oz, Dorothy reaches for the knocker and we hear the overdubbed knocking sound before she touches it. (00:58:45)
Suggested correction: The sound we hear before she starts knocking is of her grabbing the knocker, and it is right on time with when she grabs it. There is no audio mistake.
Continuity mistake: As they all leave the poppy field the artificial snow has been neatly swept off the Yellow Brick road, and all traces of the snow on the ground are gone in the next shot. (00:57:30)
Continuity mistake: As Dorothy walks on the pigsty there are two grown pigs and about eight piglets in there. When she falls in more than 12 grown pigs now appear in the sty. (00:03:55)
Revealing mistake: Throughout the movie, the tin man's costume wrinkles up.
Continuity mistake: As the Tin Man crowns the Cowardly Lion watch closely as he flings his ax behind him and it falls off the edge of stage. Two shots later its back again resting on the steps. (01:06:00)