All the kids really play their instruments, and the backup singers are real vocalists. Jack Black also played a bit of guitar in the movie (for example, when he is teaching "Smoke on the Water," "Iron Man," and other songs to Zach), but he didn't do the guitar solos.
The rock band Led Zeppelin are notoriously hesitant to allow their music to be licensed for commercial purposes. Knowing this, Richard Linklater filmed a plea by actor Jack Black in front of 1,000 screaming fans, imploring the band to let the production use the "Immigrant Song" in the movie. The plea worked and the filmed request is included on the DVD. Aptly enough, Jack Black introduced the band's three surviving members Robert Plant, Jimmy Page and John Paul Jones, when they were the recipients of the esteemed Kennedy Center Honor in the presence of President Barack Obama and First Lady Michelle Obama (20 December 2012).
Early in filming, an insecure Robert Tsai approached director Richard Linklater and tried to talk him out of letting him be in the film because he felt he wasn't right for the part. Linklater responded that it was his very insecurity that made him exactly right for the part, and kept him in. Ironically, Tsai's character, Lawrence, has a very similar conversation with Dewey Finn (Mr. S) about not feeling right for his part in the band.
Miranda Cosgrove, who plays Summer in the movie, can sing. She took about a 45-minute "bad singing" lesson to sing horrible for the song "Memory" when Jack Black's character was looking for backup singers.
The idea for the movie came when writer Mike White moved into an apartment next to Jack Black. White would often find Jack Black running naked through the halls or blasting much of the music featured in the movie at full volume.
Although the children in the film are supposed to all be the same age, the child actors ranged in age from Kevin Alexander Clark, who was nearly 15 by the time of the film's release, to Miranda Cosgrove, who has just turned 10 by the time of the film's release.
When Ned asks Dewey to sell one of his guitars to pay rent, Dewey replies, "Would you ask Picasso to sell one of his guitars?" and Sarah Silverman's character calls him an idiot. Guitars are a prominent subject in many of Picasso's paintings.
When the class are at the tryouts for the Battle of the Bands contest, Summer and Dewey are on the stage talking to the director. In this scene, when Jack Black's character gets frustrated, he throws a chair. According to the commentary on the DVD, this wasn't part of the script and Miranda Cosgrove didn't know this was going to happen. You can see her react by jumping when the chair is thrown. This is a completely real reaction.
Dewey's nickname for Freddy the drummer, "Spazzy McGee", is a reference to an early draft of the character in which Freddy is a spastic sufferer of Attention Deficit Disorder (ADD) and can be seen taking Ritalin during class.
There was a part in the original script where Freddy Jones, played by Kevin Alexander Clark, would forget his drumsticks to class and having Jack Black to say: "Would Keith Moon forget his sticks? No! He might get drunk and pass out on the floor, but he would never forget his sticks!"
Originally in the script, Dewey was supposed to have run the teacher over before she came to school which stopped her from teaching the class for 3 weeks. After, they changed it to her falling in the shower instead.
After the first band rehearsal, Dewey gives the kids some musical albums to listen to at home for inspiration and influences. The albums are: "Led Zeppelin" by Led Zeppelin, "Parallel Lines" by Blondie, "Fragile" by Yes, "2112" by Rush, "Axis: Bold as Love" by Jimi Hendrix and "Dark Side Of The Moon" by Pink Floyd.
When asked for his opinion about testing from the other teachers, Dewey dodges the question with song lyrics including the line "Let the children's laughter remind us how we used to be". One of the teachers asks if it is from a song, but he denies it. They are in fact from the song, "Greatest Love of All".
The original screenplay was called "The School of Rock", and it was later shortened to "School of Rock". However, the opening credits had already been designed and partially shown in theaters with the word "The" in the title. Director Richard Linklater decided not to digitally remove the extra word from the credits.
In Spain, Jack Black was dubbed by singer-actor Dani Martín. Martin had no dubbing experience but it was chosen because in the time of the movie his rock band "El Canto de Loco" was a big hit in Spain. This dubbing is considered one of the worst dubbing ever made in Spain due to Martin's casting choice.
The riff of The Darkness song "Black Shuck" is used in the film, but "Growing On Me" appears on the soundtrack. This is because Black Shuck contains the line "Black Shuck, that dog don't give a fuck" repeatedly.
The big posters in Dewey's bedroom are of Sex Pistols, The Who, and New York City rock band Evil Jake. They were included because set designers photographed lead singer Mike Jacobs' apartment as research on how struggling musicians actually live, and Dewey's apartment is partially modeled on Mike's.
During the class lectures, Dewey shows a slide-show that features a picture of the Ramones. In the end credits scene, Zack is wearing a Ramones t-shirt, showing how thoroughly he has changed from the beginning.
In 2014, it was announced that Andrew Lloyd Webber was working on a musical adaptation of the film. It is set to head to Broadway in November 2015 at the Winter Garden Theater, starring Alex Brightman as Dewey Finn.
When Miranda Cosgrove's character sings badly as an audition for a backup singer, she sings "Memory" from the Broadway musical Cats, which was written by Andrew Lloyd Webber. Webber would go on to write the music for the Broadway musical version of School of Rock.
The scene where Dewey confides to Ned that he has been impersonating him was originally filmed in the kitchen, including Patty. As Ned tries to call Horace Green about his mysterious check, Dewey sets a piece of paper on fire, Patty flails around the room trying to put it out, and Dewey grabs the phone away from Ned to call 911. This approach was replaced with the final version in the living room, without the fire, having only Dewey and Ned speaking heart to heart.
In a scene in the classroom, Jack Black's character can be heard playing guitar and humming to a tune similar to the theme of "Computerman". Computerman was an online Channel 101 series featuring Black in 2003.
During the Battle of the Bands scene, four stacks of Marshall amplifiers are positioned behind the kids on stage. Three of them are modern models, easily rented for a film shoot. However, the Marshall behind Tamika is a much older, "plexi" version, which is rare, and hard to come by. People generally covet these vintages, not rent them.
The Mooney Suzuki: As Dewey heads into the Battle of The Bands contest towards the end of the film he walks through a corridor and past two musicians wearing shades, leaning against a wall. The two are members the band who provide extra instrumentation on the soundtrack.