Revealing mistake: When the Plastics are walking down the hallway together, Cady falls into a trashcan. The trashcan stays upright, but it should tip over from the way she went in, the momentum and her bodyweight. Just a few shots prior to this, a janitor, on the left side of the screen, is seen moving that trash can, so it is apparent that it is not bolted to the ground. (00:44:00)
Continuity mistake: When the Regina posts the Burn Book around school the "wanna-bees" are fighting. One girl goes, "You bitch!" and the other goes "You're the bitch!" and they start to fight. While they are fighting they jump onto a table and it breaks. If you look into the backround, you see Jason and his 2 friends turn around because they heard the noise of the table breaking and the girls fighting, and Jason's friend on the right puts his hand on Jason. When the camera changes shots his hand is on his heart.
Continuity mistake: When Regina is by her car after Cady's party, Regina says something about the Caltine bars and her boyfriend says that they are for weight gain. Regina spits it out and at one point you can see her boyfriend putting his cup up to his lips, then the shot changes to the other side of the car and his arms are down straight.
Continuity mistake: In the 'Jingle Bell Rock' scene, right after Gretchen kicks the stereo off the stage, you see her feet, and they are both symmetrical next to each other, then when you see her again one of her feet is behind the other.Gretchen does not move at all between email@example.com