Continuity mistake: In the bar scene at the end of the movie Stanley dives over the bar while Dorian's thugs shoot at him, when they stop shooting you see one of the thugs drop the magazine out of the gun then the scene cuts away from him and when it cuts back you see the thug drop the magazine out of the gun again.
Continuity mistake: When Dorian dismisses his charges to capture the Mask for 50,000.00, Tina and Dorian chat. She is about to light her cigarette but doesn't. In the next cut away there is smoke in the air but she still hasn't lit it yet. As the scene continues you only see smoke when Diaz has her back to the camera.
Continuity mistake: When Stanley Ipkiss first appears as the Mask, after having jumped through the end of hall apartment window with Mrs. Peenman shooting at him, he is approached by several thugs, one of which asks him the time. The thugs begin chasing him down the alley. The thug with the beard and baseball cap at the beginning of this chase is shirtless. Halfway through the chase he now has a flannel shirt on which is unbuttoned, (visible when he jumps over a barrel as it flies open). As he stops, now the flannel shirt is buttoned up to the very top button. The entire chase scene is 4-5 seconds long.
Continuity mistake: In the very beginning, when the scuba diver is trying to open the chest and gets hit with the pipe, at first the pipe is held by a rope near the middle and when it's lowered into the water it is held by a chain at each end. After it hits the guy and is let go from the chains they are wrapped around three times.
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.