Continuity mistake: When TJ comes to school in the morning and everyone starts cheering, we see two Ashleys clapping with everyone else. As the camera follows TJ as he walks to the entrance, we see the same two Ashleys a second later.
Continuity mistake: When TJ announces that there will be no gum sharing, it shows Gretchen in the classroom. There is a kid sitting behind her. However, this is the same kid who is caught running in the hall, who Ms. Lemon says is a sixth grader. The gang is in fourth grade.
Continuity mistake: When the gang is eating lunch, there is a girl in a pink shirt and some other people at the table behind them. When it cuts to behind Prickley and TJ, the kids at that table are different.
Continuity mistake: After T.J. has become principle for a day, it shows him chewing out a kid for running in the halls. He throws down a manilla folder onto his desk in anger. However, when the shot changes, the folder has disappeared.
Continuity mistake: When Randall and TJ are walking across the playground, Randall's hair has turned black and so has TJ's hat.