In suburban Chicago, near the end of the school year, high school senior Ferris Bueller fakes illness to stay at home. Throughout the film, Ferris frequently breaks the fourth wall to talk about his friends and give the audience advice on various subjects. His parents believe he really is ill, though his sister Jeanie does not. Dean of Students Edward R. Rooney suspects Ferris is a repeat truant and commits to catching him. Ferris convinces his best friend Cameron Frye, who is legitimately absent due to illness (though a hypochondriac, which Ferris sees through), to help lure Ferris’ girlfriend Sloane Peterson from school on the pretext of her grandmother’s supposed demise. To further the ruse, Ferris borrows Cameron’s father’s prized 1961 Ferrari 250 GT California Spyder. Cameron is dismayed when Ferris takes them into downtown Chicago in the car, to spend the day. Ferris promises they will return it as it was.
The trio leave the car with parking attendants, who promptly take the car for a joyride. The trio explore the city, including the Art Institute of Chicago, Sears Tower, Chicago Mercantile Exchange, and attend a ball game at Wrigley Field, while occasionally their paths intersect with that of Ferris’ father. Cameron remains uninterested and worried, and Ferris attempts to cheer him up by joining a parade float during the Von Steuben Day parade and spontaneously lip-syncing Wayne Newton’s cover of “Danke Schoen”, then moving into a rendition of The Beatles’ “Twist and Shout” that excites the gathered crowds.
Meanwhile, Rooney prowls the Bueller home attempting to prove Ferris’ truancy, getting into several pratfalls. At the same time, Jeanie, frustrated that the entire school supports and will rally for Ferris, skips class and returns home to confront him. She is surprised by Rooney’s presence at their home and knocks him unconscious. As she phones the police, he gains consciousness and goes back outside, unknowingly leaving his wallet behind. When the police arrive, they disbelieve her and place her under arrest for making a false report. Waiting for her mother to collect her from the police station, she meets a juvenile delinquent who advises her not to worry so much.
The friends collect the Ferrari from the parking lot and head home. Discovering many more miles on the odometer, Cameron becomes catatonic with shock. Back at Cameron’s house, Ferris jacks up the car and runs it in reverse to “rewind” the odometer. This does not succeed and Cameron finally snaps, letting out his anger against his overbearing father. Repeatedly kicking the car causes the jack to fail and the car races in reverse through the wall and into the ravine below. Ferris offers to take the blame, but Cameron declines the offer and decides he will stand up against his father. Meanwhile, Mrs. Bueller arrives at the station, upset about having to forgo a house sale, only to become infuriated to find Jeanie kissing the delinquent.
Ferris gets Sloane home and realizes his parents are due home any minute. As he races on foot through the neighborhood, he is nearly hit by Jeanie, who is driving their mother home. She speeds off trying to get home before him and expose his lie. Ferris makes it home first but finds Rooney there. Jeanie races into the house as their mother complains to their father about her behavior. Jeanie discovers Rooney threatening Ferris and thanks Rooney for helping return Ferris ‘from the hospital.’ She displays Rooney’s wallet as proof that he was the one that broke into the house and Rooney gives up. As Rooney flees from Ferris’ dog, Ferris rushes back to his bedroom to greet his parents when they check in on him. Finding him sweaty and overheated (from his run) they suggest he might want to think about taking tomorrow off as well. As the parents leave, Ferris reminds the audience, “Life moves pretty fast. If you don’t stop and look around once in a while, you could miss it.”
During the end credits, a defeated Rooney heads home and is picked up by a school bus, where he is further humiliated by the students. After the credits, a surprised and slightly annoyed Ferris tells the audience the film is over and to go home.