Revealing mistake: The glass in Dorothy's bedroom windows don't break, they are removed from their frames as the scene progresses, and if you look at the reflections in them the windows are made of plastic. (00:18:45)
Audio problem: The talking tree grabs Dorothy before he throws his apples. She starts screaming. And as she runs off laughing. Her lips don't match what we're hearing. (00:40:10)
Plot hole: When the Gales' house lands in Munchkinland, Dorothy picks up Toto and glances around the house. She looks right out the window. Wouldn't she have noticed that she wasn't in Kansas then, before she got to the door? (00:19:05)
Other mistake: When Dorothy's house is falling back to Kansas, just before it lands, there is about a 1 or 2 second shot of what looks like production notes written in blue ink.
Suggested correction: There are no production notes visible anywhere.
Continuity mistake: When the Tin Man is telling his story, as he says "I was chopping that tree," Dorothy starts to look at the tree he's referring to, but in the next shot, she's looking right at the Tin Man again.
Continuity mistake: In the beginning of the movie Dorothy comes running into the farm and there's an old tire hanging from a tree. Two shots later as she walks away from Aunt Em and Uncle Henry the tire has been moved. The angle at which it hangs has been changed and the piece of rope hanging on the bottom of it is now three or four inches closer to dead center than it was before. (00:03:00)
Audio problem: Dorothy yells, "help, help" as she's chased by the flying monkeys but if you look at her mouth she's yelling, "Oh, Oh". (01:15:20)
Continuity mistake: Just before Aunt Em and the others go into the storm cellar there are two glass jugs on top of the shelf on the right of their back door. When we see the spot again a few seconds later as Dorothy stands there the jugs are gone. They're not on the floor either. (00:16:40)
Continuity mistake: As Toto escapes from the Wicked Witch there's a mortar and pestle to the left of the hourglass. In a close-up Dorothy looks at the hourglass after the Wicked Witch turns it over and we see the pestle has been moved to the other side of the mortar. There will be no confusion about this if you look at the direction of the shadow cast by the hour glass. (01:18:20)
Continuity mistake: Inside the Emerald City, when they are at the palace entrance, the guard's mustache is turned up in the first shot, and is turned down in his next shot. (01:04:45)
Continuity mistake: When Toto escapes, he runs up to the three putting the Scarecrow back together and the Tin Man has nothing in his left hand. In the next shot the ax appears in his hand. (01:19:40)
Continuity mistake: As the Wicked Witch is melting the peak of her hat stays intact. In the very next shot it has been flattened. (01:26:45)
Continuity mistake: In the very beginning of the film, as Dorothy and Toto are running down the road towards the farm, you can see a small grease spot on Dorothy's apron when she reaches down to pick Toto up. When they reach the farm, somehow the spot has vanished.
Continuity mistake: In the poppy field, when Dorothy points at the Emerald City, the Lion is standing more than a meter away from her. In the close-up he stands very close to her.
Continuity mistake: In the haunted forest, when the Tin Man is lifted up in the air, the Lion crouches and covers his face with his paws. A frame later he is standing up in a totally different position.
Continuity mistake: Aunt Em places a cold towel on Dorothy's head. The towel is sometimes away from the eyebrow, slightly on top, or completely covering it, depending on the angle.
Continuity mistake: The Lion says, "Read what my medal says," and holds it with his paw. In the close-ups the paw is away and the medal lies flat on his chest.
Continuity mistake: When water falls on the witch, a guard on the left disappears.
Continuity mistake: Dorothy's Aunt hands out some food, walks with her and leaves Dorothy alone. Several meters ahead there's a cart wheel and one chicken. When the angle changes, Dorothy is standing next to the wheel, which is also facing a different position, and there's a lot of chickens around.
Other mistake: As Glinda walks over to meet Dorothy, the bridge is the same but the background behind her changes between shots. (00:21:30)
