The eponymous album was released on September 30, 2003. Sammy James Jr. of the band The Mooney Suzuki penned the title track with screenwriter Mike White, and the band backed up Jack Black and the child musicians on the soundtrack recording of the song. The film's director, Richard Linklater, scouted the country for talented 13-year-old musicians to play the rock and roll music featured on the soundtrack and in the film. The soundtrack includes "Immigrant Song" by Led Zeppelin, a band that has rarely granted permission for use of their songs in film and television. Richard Linklater came up with the idea to shoot a video on the stage used at the end of the film, with Jack Black begging the band for permission with the crowd extras cheering and chanting behind him. The video was sent directly to the living members of Led Zeppelin, and permission was granted for the song. The video is included on the DVD.

Who wrote the song in school of rock? Okie... think carefully first, then make a decision:
To answer the question, consider the following: Sammy James Jr. of the band The Mooney Suzuki penned the title track with screenwriter Mike White, and the band backed up Jack Black and the child musicians on the soundtrack recording of the song. So, the answer is Sammy James Jr. of the band The Mooney Suzuki.