Josie Geller (Drew Barrymore) is an insecure 25-year-old copy editor for the Chicago Sun-Times who has never had a real relationship. One day, her editor-in-chief, Rigfort (Garry Marshall) assigns her to report undercover at a high school to help parents become more aware of their children's lives.
Her first day at South Glen South High School is miserable. Josie reverts to the old geek persona that ruined her first high school career. She also has an unfortunate run-in with three obnoxious popular girls (Jordan Ladd, Jessica Alba, and Marley Shelton), and Guy Perkins (Jeremy Jordan), the school's most attractive, popular student. Josie loses hope, but is reassured when a kind-hearted nerd named Aldys (Leelee Sobieski) befriends her. Aldys, who loathes Guy and his gang, invites Josie to join The Denominators, a group of intelligent students.
Josie develops a crush on her English teacher, Sam Coulson (Michael Vartan), and becomes the top student in his class. After reciting a romantic excerpt from Shakespeare to Sam, Josie has horrible flashbacks to when she read a romantic poem aloud in class to her high school crush, a popular boy named Billy Prince (Denny Kirkwood), who later asked her to their senior prom, making her dream come true. However, on the night of the prom, Billy arrives with another girl and both of them hurl eggs and insults at Josie, humiliating her and breaking her heart.
One night while out driving with Aldys, Josie encounters Guy and his gang at a local hangout called "The Court" where promiscuity and underage drinking take place. Her managing editor Augustus "Gus" Strauss (John C. Reilly) loses patience with Josie after a rival paper scoops The Court story, and orders Josie to become friends with the popular kids. He arranges for her to wear a hidden camera, and soon the whole office becomes obsessed with her story.
Josie confides in her brother Rob (David Arquette) about her fears. Rob, who was their high school's most popular boy in his teens, urges her to let go of her old self and start anew. To help her, Rob enrolls as a student and becomes an instant hit. He then uses his influence to draw Josie into the cool crowd, much to the dismay of Aldys.
Sam and Josie grow closer, but Sam struggles with his feelings as he thinks she's a student. Guy and Josie attend the prom as Rosalind and Orlando from Shakespeare's As You Like It. Anita, Gus and Josie's other co-workers watch through the camera and are overjoyed as she is voted prom queen. As Guy dances with Aldys as an alleged act of friendship, the mean girls attempt to dump dog food over Aldys. Outraged, Josie throws her crown away and reveals her true identity. She praises Aldys for her kindness and warns the students that one's persona in high school means nothing in the real world. Sam is hurt by her lies and states he wants nothing to do with her. Also angered is Rob, who as a phony student received a second chance at baseball. Josie, ultimately making amends, secures him a coaching job.
Josie vows to give Gus a story and writes an account of her experience. In it, she admits she's never been kissed, describes the students of South Glen South, and avows her love for Sam; the entire city is moved by it. She writes she will stand in the middle of the baseball field and wait for Sam to come and kiss her. Josie waits, but the clock runs out with no sign of Sam. On the verge of giving up... cheers, then a booming roar, as Sam emerges to give her a romantic kiss.
During the scene where Josie and Aldys are talking to each other on the football field, the band plays the theme song from The Simpsons.
During a scene where Josie is remembering her bullying in high school, Cyndi Lauper's "She Bop" is played.
"(I Just) Died in Your Arms" by Cutting Crew plays when Josie first sees Guy entering the classroom.
American ska band Spring Heeled Jack U.S.A. submitted a song named "Josie" for the film's soundtrack. The band had previously released a single titled "Jolene" which was about their tour van, but when given the opportunity to submit a song for the soundtrack, they simply replaced the name Jolene with Josie to make it relevant to Barrymore's character in the film. It was later rejected.
Kottonmouth Kings' "Suburban Life" plays when Josie pulls up to the school and her car backfires.
The song "Peppyrock" by BTK is featured in the movie.
South Glen High School was filmed at John Burroughs Middle School located in the Hancock Park area of Los Angeles at 600 South McCadden Place
Josie's childhood home is located at 368 North Ridgewood Place in the Hancock Park area of Los Angeles.
Nana's coffee shop where Josie and Aldys have lunch is the Monrovia Coffee Company located at 425 South Myrtle Avenue in Monrovia, CA.
The Tiki Post where Rob worked is now a Cold Stone Creamery located at 408 South Myrtle Avenue in Monrovia, Ca.
The exterior scenes for the prom were filmed at 4526 Wilshire Boulevard in Los Angeles, CA. The interiors were filmed at the Ebell located at 743 South Lucerne Boulevard in Los Angeles, CA.
Josie's office and job scenes were filmed in Chicago and readers of the Chicago Sun-Times were shot on the Chicago Avenue stop on the CTA Brown Line.
Critics gave mixed reviews to the film, with a "Rotten" score of 57% on review aggregation website Rotten Tomatoes, and its consensus reading: "Unoriginal and unremarkable high school satire adds little to the Genre."