When Dewey Finn, a passionate but irresponsible rock guitarist, gets kicked out of his band and faces a mountain of debts and eviction, he adopts a desperate plan to earn money. Posing as his roommate Ned Schneebly, Dewey accepts a substitute teaching job at a prestigious prep school. Initially indifferent to the academic environment, Dewey quickly discovers that his class of straight-A students harbors a variety of musical talents. Struck with an idea, Dewey decides to form a new band with the kids in secret to win a local Battle of the Bands and claim the prize money to solve his financial troubles.

As Dewey introduces his unconventional teaching methods, he instills in his young students a love for rock music and self-expression, breaking them out of their academic restraints. While educating them on the history of rock and fine-tuning their musical skills, he also emphasizes the importance of embracing their individuality. Meanwhile, Dewey must keep the faculty, especially the strict and skeptical headmistress of the school, from discovering the unconventional curriculum he's delivering to the children. With the Battle of the Bands fast approaching, Dewey becomes committed to seeing through this deception, all while the transformative power of music and his unconventional teaching begin to leave a lasting impact on his students.