Factual error: When Arriety and Spiller are rescuing Peagreen from the bottle, Arriety introduces Peagreen to Spiller. But later on when her parents show up and she introduces Spiller to them, she also introduces Peagreen to Spiller again.

Factual error: Although cars are seen driving on the right-hand side of the road for most of the film, one overhead shot shows UK-style "give way" lines across the left-hand side of the road.

Continuity: When Mr Potter removes the stuff that the exterminator accidentally sprayed on his face, it's thicker than in the previous shot.

Plot hole: How could Pod have been sure that Pete would have all the things he needed, when he is preparing to rescue Peagreen from the milk bottle?

Continuity: I don't know the race of the exterminator's dog, but she's of a different one during one shot, when he finds her after she ate milk products in the factory.

Other: When Arrietty and Pea-Green slide along the power line, they go pretty far. They would have hit a post and gotten electrocuted.

Other: At the beginning, when Pod is climbing up the table, he does it in seconds. There's no way he could have gotten up that fast.

Revealing: Whenever there is a bird's eye view of the town, you can see that the far backgrounds are paintings.