Continuity mistake: When Dorian puts on the mask for the first time, right before all the smoke starts reducing, pay close attention to his goons. Some of them change position. (Clearly those were two takes pasted together, one with Dorian without the mask, and one with.) (01:04:25)
Continuity mistake: When The Mask first visits the Coco Bongo and dances wildly with Tina, they perform a series of impressive manouvers and The Mask then dips Tina and holds her in that position. At this moment, Tina is revealed to be a stunt double, not Cameron Diaz, just before the camera zooms into a close up of Jim Carrey.
Continuity mistake: When Dorian's boss shoots him in the stomach it switches from the boss to Dorian several times. Each time Dorian's buttons change colours from black buttons to white buttons to no buttons. (01:18:25)
Continuity mistake: When Tina goes to the jail and meet Stanley they almost kiss for the first time. She is wearing bright red lipstick. A few minutes later she is running down an alley outside of the prison from Dorian. She is wearing soft pink lipstick. (01:09:00)
Continuity mistake: While in Mrs. Peenmans' hall, just before she shoots him, his hands switch places on the mallet. In the first shot, his left hand is on the bottom, right hand is on the top. In the other two shots, it is vice-versa. (00:18:15)