Continuity: In the shot just before Jules' friend asks, "Can you get us booze?" Seth's collar is folded inwards. In the shot just afterward, it's unfolded, partially obscuring the strap on his bag.

Continuity: In the scene where Evan is getting up from lunch with Seth, the bag of food he has is facing open towards Seth, but a few shots later the open side is facing to the right.

Continuity: When the fake ID is first seen in the movie, the back of the ID is blank white. But later on when it is seen again, the back of the ID has black print all over it.

Continuity: When Seth and Evan are waiting outside of the liqour store for Foggel, Evan's condom and lubricant changes hands towards the end of Seth and Evan's talk.

Continuity: When Evan is talking to Becca by the lockers about Jules' party, a black guy with a stripy shirt walks across the scene. As soon as the camera shot changed to Becca's view, the same guy is behind Evan and about to walk past them again.

Continuity: When Seth is dancing with that girl at the party, notice she is holding a bottle of beer. In one of the following shots, if you look closely, she is not holding it, but in the very next shot she is holding the beer bottle again.

Revealing: When McLovin' is in the car with the police, if you look really closely through the reflection from their glasses, you can see the green screen that is used in movies. When the scene shows the outside of the car, there is nothing around them that would reflect the screen.

Continuity: After Seth goes to "rob" the supermarket's liquor, Fogell and Evan are talking about Fogell's TV. However, in the next shot, they seem to be standing in the same position, but in another place completely. The supermarket behind them is no more; there are shadows upon them even though they were standing in the sun the previous shot; the parked vehicles behind them change completely; they stand closer to the parking area; and even the time of day is not the same (from sunset, since it's after school, to midday). Also, Evan points at the off-screen Seth, somewhere on the left side of the screen, yet he should be behind them. Note that it is the same scene.

Revealing: Seth is seen holding the alcohol-filled detergent containers, waving his arms and saying to Evan, "You bailed on me!" If the containers were truly full, or even half full, they would be too heavy for him to move up and down so easily. They were obviously empty.

Continuity: When Seth is telling his Home Ec. teacher that the class is a joke, the teacher's mouth changes from really wide to slightly open.

Character mistake: When they are in class at the beginning, the teacher is talking about imaginary numbers and says that i multiplied by i equals 1, but i multiplied by i actually equals -1.

Continuity: When McLovin is being questioned by the cops in the liquor store, the two policemen are standing next to each other, almost elbow to elbow. However, the shot of Evan and Seth viewing this through the window, the two cops are now several feet apart.

Continuity: During the scene in which Evan and Seth first talk to Fogel about the fake I.D. several students are seen changing positions during shots. Most notably the white girl in a blue shirt standing in the backround between Evan and Seth being replaced by a black guy in an unrealistic time frame in between shots.

Continuity: Jonah Hill, the actor who plays Seth has attached ear-lobes while the actor who plays him as a child has unattached ear-lobes.

Factual error: When Fogle shoots the cop's pistol at the burning police car, the safety on the Smith and Wesson pistol is activated. He fires the weapon until it is empty and continues to dry fire (click) the pistol anyway. On the Smith and Wesson, the side levers are in Safe mode when pushed down. When the last round is fired, the slide locks back and the gun wouldn't be able to dry fire.