After Dewey and Miss Mullins go to the bar, Dewey is heard singing and snapping his fingers as he drives. However, you can see through the windshield that both of his hands are on the steering wheel and he is not snapping his fingers.
During the Battle of the Bands performance two different guitars can be heard on the audio track playing at the same time, although for most of the song Dewey is not playing his guitar and Zack is the only other guitarist on stage.
While Zack is playing his newly composed song in the background as Billy and Dewey are discussing the band's outfits, you can hear the chords and notes change, yet Zack's fingering doesn't change for the last part in the shot.
During the music montage set the the music of the Ramones, Dewey can be seen demonstrating different rock and roll facial expressions to Katie while playing the bass. The problem is, however, that the bass he has on and is demonstrating with has no strings, even though he is moving his fingers as if it does.
When the school band begins to play "School of Rock" there is a Hammond organ sound heard playing through a rotating Leslie speaker. Lawrence is playing the Yamaha keyboard and the Hammond and Leslie are behind him.
After the band have performed their song at the concert, Dewey tells Gordon that the lights were awesome. While this happens, one of the girls in the group comes over to them and calls Dewey "Jack", as in Jack Black the actor's name.
The title of the movie is "School of Rock". The only time it is referred to as "The School of Rock" is a neon sign at the very beginning. The directors commentary addresses the titling error and specifically states that the title is "School of Rock."
Following School of Rock's performance at the Battle of the Bands, Miss Mullins is stopped by security and then allowed access backstage by claiming, "I am principal of the school's band." In reality, she is principal of the band's school.
Towards the beginning of the movie, Summer clearly states that her parents pay 15,000 dollars a year for her tuition. When the angry parents confront Principal Mullins after parent night, Summer's mother shouts numerous times "I do not pay 15,000 dollars a month for my child...".
When they get to the Battle of the Bands, he tells the woman, "We are competing. We are the School of Rock." They were already on the bill, and then the name of the band happened later, and there didn't seem to be any time for the person backstage to have that name listed on her clipboard.
When "School of Rock" are on stage for their big show, Dewey enthusiastically plays the lead guitar break after the first verse, where he starts dramatically flailing and stomping around the stage. Looking closely you can see his feet getting dangerously tangled in the blue guitar cord used by Katie on bass. In the next shot from a different angle, however, that specific blue cord is nowhere to be seen on the floor near Dewey's guitar theatrics.
When the parents of the kids are interrogating Dewey Finn, the police arrive to arrest him, Principle Mullins arrives too and so does his friend Ned Schneebly and his friend's girlfriend Patty Di Marco. They all stand at the door leaving absolutely no space at the entrance of the classroom. In the next scene Finn is seen running away in the corridors of the school from everyone due to a verbal misunderstanding between him and the parents. It is unclear how he was able to escape from the classroom since the entrance was completely blocked by the police, Mullins, De Marco and Schneebly in the previous scene.
When Summer is waiting for Dewey to arrive so she can explain her argument about not wanting to be a groupie, she's seen leaning against a tree with no lipstick, but when she approaches Dewey she's wearing bright red lipstick.
Just after Freddy and Katie show off their glam-rock costumes to a horrified Dewey, they and the rest of the band go to play Zach's song. Mid song they go from their costumes back to their school uniforms.
Just prior to the band prayer, when the kids put their hands
in the middle, in one shot Tomika is very quick to put her hand in the middle. In the close-up of the hands her hand is one of the last to be put in the middle.