Continuity mistake: At the beginning of the movie, Oz gives his new assistant a gift, and leans in for a kiss. Both of them are seen to tilt their heads to their right for the kiss. The scene cuts to a wider shot, just before Frank barges in, and their heads are tilted to the left.
Continuity mistake: After Oz and Theodora have climbed down from the small cave where they hid from their first encounter with a flying baboon and are having a brief conversation, the brim of Theodora's hat alternates from being held up on her right side in the shots from behind her, and being down as it normally is in the shots from in front of her. Presumably this was done to prevent the hat brim from obscuring Oz's face.
Continuity mistake: After Oz tells Finley he'll get a nice big pile of bananas, Finley tosses down Oz's bag and goes on a rant about monkey stereotypes. When he first throws down the bag, he is close to the middle of the yellow brick road. It cuts to a close up and he is suddenly standing right next to the edge of the road.
Continuity mistake: Throughout the film, Glinda's hair continuously changes from being curled to straightened to curled again. This occurs often, and on occasion within the course of a single scene (for example when she introduces Oscar to the residents of Oz).