Set in a suburban California high school, the film follows a group of students navigating the trials of adolescence. Stacy Hamilton, a sweet and naive sophomore, is eager to dive into the world of dating and relationships, encouraged by her confident friend, Linda Barrett. Mark Ratner, a shy but kind-hearted student, struggles to muster the courage to ask out Stacy. His friend, Mike Damone, a self-assured ticket scalper, offers him dubious dating advice. Meanwhile, Brad Hamilton, Stacy's older brother, has his own troubles as he juggles a string of part-time jobs while trying to maintain a sense of purpose and maturity.

At the center of the high school chaos is Jeff Spicoli, an easygoing, perpetually stoned surfer who clashes with his strict history teacher, Mr. Hand. Throughout the first half, the characters face various humorous and poignant situations, revealing the pressures and excitement of teenage life. The story weaves together their overlapping experiences, touching on themes like identity, ambition, and the pursuit of happiness. Each character's journey is marked by moments of growth and self-discovery, setting the stage for the developments that follow as they each confront more significant challenges in the latter part of the film.