Goofs

A scene where A Plus flees down the stairs and cloaks into a crowd of students by the lockers in the school's corridor, bullies chase after him and trail behind a chubby school boy in a striped green and white polo shirt and denim shorts in the process. In the following scene, Ace Ventura Jr. rushes down the stairs aside the exact same chubby boy from the scene before as if he had not been ahead of the bullies searching for A Plus.

When they are in the cafeteria, originally there were 3 food trays on the table and by the time they leave there is just one.

As the prison bus carrying his mother drives away, a camera man is visible in the bus window's reflection.

Near the beginning of the movie Ace saves a rodent from a trap. The characters, who are supposed to be animal experts, refer to it as a mouse but it is clearly a rat, mice are much smaller.