All of the children are competent musicians, and they are all playing their own instruments.

Miranda Cosgrove, who plays Summer Hathaway, actually has a really good voice and plays guitar. She had to take a 45-minute class to learn how to sing badly for the one scene where she sang "Memories."

In the second cafeteria scene, the blonde girl seen sitting at a lunch table behind the teachers lunch table is Freddy Jones' (played by Kevin Alexander Clark) sister in real life.

In the picture that Huey shows Ned of their old band, we see Black and White in the picture with another in the back. The third man in the back is the director of the film, Richard Linklater.

At the beginning of the movie, when the band fires Dewey Finn, he says something like, "I'll make it and you'll just be a kick on my epic ***." Epic Records is the company who produces Jack Black's real CDs.

During ending credits, when the band is playing, the actors were all wearing their own clothes. The bass player (Katie) actually had a solo as well, but the editors cut it out.

Gibson, one of the most expensive guitar brands in the world, donated ten standard SGs (the red guitars that are seen throughout the film, and the one Dewey is playing on the poster) to the film. Jack Black (Dewey) now owns six of them, because he "got there first."

The final sequence during the credits was all unscripted. Both the dialog and music solos were improvised.

Dewey's friend and roommate Ned Schneebly is played by Mike White, who also wrote the screenplay.

Screenwriter Mike White isn't a fan of classic rock. The movie was written specifically so Jack Black could perform his own favorite rock music.