Continuity mistake: After a passing train disturbs the Mousekewitz's home and extinguishes their candle, Papa strikes a match and lights it up. He tosses the match somewhere offscreen, but one shot later it appears right in front of his feet.
Continuity mistake: After Fievel reunites with his family at Green River, he can be seen sitting on a pair of saloon doors. But right before a cat busts through them, Fievel switches from one door to the other between shots.
Continuity mistake: When Tiger is hanging onto the train bound for Green River, a dog rips a large chunk of fur from his tail. But as Tiger gets thrown from the caboose into the path of another train, his tail has regrown all of its lost fur, within the span of two shots.