Continuity mistake: When TJ is making the morning announcements, the Ashley who wears green is sitting behind Spinelli. When he says there will be dessert after lunch, the desk behind Spinelli is empty.
Continuity mistake: When TJ makes the morning announcements, in the first scene of the classroom we see a boy in a blue hat sitting in the back row. After TJ says that the kids can refuse to answer a teacher, the same kid is suddenly sitting in the second row so he can slap hands with someone in the first row.
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 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 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.