Continuity mistake: When Toto pulls the curtain back to show who the real "Oz" truly is it looks like Toto's collar got snagged or he actually had to bite it but in the next shot he pulls the curtain back so fast that it would've sent Toto flying but then he is connected back to it again.
Continuity mistake: The Wicked Witch of the West's bilious green face colouring changes shades during the film. DVD showing.
Continuity mistake: When Toto escapes from the witch's castle and runs off to the Tin Man, the Scarecrow and the Lion to lead them to rescue Dorothy, he can be heard barking. As he is running up to the three, he is still barking, but his mouth is quite still and his tongue is hanging out. (01:19:30)