Continuity mistake: In the Home Ec. class, Seth has coco powder on his apron. When talking to Fogell, the amount of powder has decreased significantly. (00:13:00)
Deliberate mistake: When young Becca picks up the drawing that young Seth made, in the first shot, as she flips it over to look at it, you can faintly see the pen-marks through the paper, and they are not the same as in the following close-up shot, when we see the actual drawing. In the first shot, they seem to be a grouping of rectangular shapes, whereas in the second shot, it is obviously a large drawing of a penis. They had to use different pictures due to child labor laws that wouldn't permit the young actress from seeing the actual picture, and so a hand-double was used for the close-up shot. (00:17:15)
Continuity mistake: When young Becca is looking at the drawing, her hands change position instantly. (00:17:20)
Continuity mistake: 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. (00:18:25)
Continuity mistake: 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. (00:24:15 - 00:40:20)
Continuity mistake: 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. (00:25:05)
Continuity mistake: 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. (00:34:00)
Continuity mistake: There is a scene where Evan, Seth and Fogell are discussing the list of liquor that Fogell is going to purchase while standing in front of the liquor store. Take notice of Fogell's left long sleeve shirt; it goes from being folded back enough to expose his wristwatch to being neatly folded down within several quick shots. (00:34:25 - 00:35:50)
Continuity mistake: 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. (00:36:45)
Continuity mistake: After Evan, Seth and Fogell run from the two cops, the boys come to a bus stop, with a bus just pulling up to it. Take notice that there are about two passengers on the bus. Upon entering the bus, not only has the number of riders increased, but you also see the bum that you should have seen in the back of the bus (Fogell encountered earlier) from the previous shot when the bus arrived. (01:20:40 - 01:21:10)
Continuity mistake: 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.
Revealing mistake: 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 mistake: The shirt that Seth got from Evans dad changes colors from blue to black and back to blue throughout the alcohol-buying scenes.
Continuity mistake: When running from the cops, the amount of booze in Fogel's bag is constantly changing. In some shots the bags are bulging, but not in others.
Continuity mistake: Jonah Hill, the actor who plays Seth has attached ear-lobes while the actor who plays him as a child has unattached ear-lobes.
Continuity mistake: 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 mistake: 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.
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.
Continuity mistake: 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.
Continuity mistake: In the scene where Officers Michael and Slater are arresting Seth and Evan, Officer Slater holds his flashlight pointing off into the trees when he draws his gun. In the very next shot of the two boys, the light from the flashlight is visible on their shirts.
