Revealing mistake: When the Wicked Witch scares the Munchkins in Munchkinland, where Dorothy lands, she disappears into a cloud of smoke she creates. But you can see her sneak down into a trap door below. [As a sidenote to this entry, Margaret Hamilton was hospitalized for severe burns after a take of this shot (not the final one used) when the stage elevator got stuck and the explosion went off.] (00:30:45)
Revealing mistake: When the Lion is pulling up the Tin Man with his tail on the way to the castle, you can see a square block inside the Lion's costume to hold the tail on. (01:20:00)
Continuity mistake: As the chandelier falls on the guards at the witch's castle, all the candles are blown out by the time it lands. The next shot shows some of them relit. (01:24:50)
Continuity mistake: When the Wicked Witch scares the Scarecrow, Dorothy, and the Tin Man with fire, after the fire is thrown, not only is the Tin Man's funnel cap on backwards, everything is reversed. In order to keep the characters oriented from left to right correctly, they had to show the film from the wrong side, thus the buttons of the Scarecrow's jacket and everything else are on the wrong side. (00:46:40)
Continuity mistake: In the scene where the Wicked Witch in Munchkinland goes over to observe the ruby slippers on her dead sister's feet, when she is up close there's not much space between her and the slippers but when she turns around and says "they're gone," she's further away, then she's closer again in the next shot.
Visible crew/equipment: While Dorothy and the other characters are cornered in the Wicked Witch's castle, when Dorothy grabs the bucket of water and tosses it at Scarecrow's arm, the water hits the Witch. In the closeup of the Witch's face, you can see a crew member's hand (a long sleeve can be seen at the wrist) in the upper left side of the shot. (01:26:20)