High school senior Ferris Bueller (Matthew Broderick) decides to skip school on a pleasant spring day by cleverly pretending to be ill, fooling his parents ([Lyman Ward] and [Cindy Pickett]). He then invites his girlfriend, Sloane (Mia Sara), and his cynical best friend Cameron (Alan Ruck) to take a memorable day trip to Chicago, just before they graduate to different colleges. Ferris crafts an intricate deception in his bedroom using a mannequin, a trophy, and his stereo to ensure no one discovers his ruse.
With a little persuasion, he convinces Cameron to borrow his father's prized 1961 Ferrari 250 GT "California", under the guise of picking up Sloane for a day of adventure. To further fool Sloane’s posh father, Cameron poses as him, claiming a family tragedy that excuses Sloane from school for the day. Meanwhile, the rest of the school becomes aware of Ferris' supposed illness, leading many to rally support in a movement dubbed "Save Ferris." However, not everyone is fooled; his sister Jeanie ([Jennifer Grey]) is furious at Ferris’ casual defiance of authority, and the school’s Dean of Students, Edward Rooney ([Jeffrey Jones]), is determined to catch Ferris in his lie.
As Ferris and his friends hit the city, they leave the Ferrari with some garage attendants, who quickly take the opportunity for a joyride. The trio spends the day exploring, enjoying a Cubs game at Wrigley Field, admiring the view from the Sears Tower, visiting the Art Institute of Chicago, and participating in the festive Von Steuben Day Parade, where Ferris joyfully lip-syncs to Wayne Newton's "Danke Schoen" and the Beatles' "Twist and Shout", dedicating the former to Cameron. Acting as the Sausage King of Chicago, Ferris dines at an upscale restaurant on Rush Street, all while carefully avoiding his father, who is out with business associates.
Meanwhile, Mr. Rooney is on a quest to find Ferris, visiting both local hangouts and Ferris’ home, where he finds himself in a series of comedic mishaps, including getting stuck in the mud and chased by a dog. Jeanie eventually returns home in search of Ferris, but instead discovers Mr. Rooney. Mistaking him for a burglar, she attacks him, leading to a hilarious misunderstanding, and even a trip to the police station. There, her encounter with a drug dealer provides her with a new perspective on her obsession with her brother.
As the day winds down, Ferris and his friends retrieve the Ferrari but are horrified to find that hundreds of miles have been added to its odometer, triggering Cameron's anxiety about his father’s wrath. Ferris devises a plan to reverse the odometer by running the car in reverse while propped up on jacks. When their plan fails, Cameron releases his pent-up frustrations about his father, culminating in a moment of defiance where he damages the car. Ultimately, the car crashes through a glass wall and into a ravine. Despite Ferris offering to take the blame, Cameron contemplates confronting his father about the truth.
After a whirlwind day, Ferris walks Sloane home before racing through backyards to avoid his returning family. However, he narrowly escapes detection when Jeanie, now appreciating her brother’s ingenuity, speeds home to beat him, even earning a speeding ticket in the process. Once home, Ferris confronts an awaited Mr. Rooney, but Jeanie cleverly plays along, fabricating a story of her brother’s illness and using evidence of the earlier incident to mislead Rooney further.
Ferris dives into bed just before his parents check on him. With a cheeky grin, he breaks the fourth wall, sharing a nugget of wisdom: > "Life moves pretty fast. If you don't stop and look around once in a while, you could miss it." As the credits roll, Mr. Rooney, still disheveled, is left to find his way back on a school bus. In a humorous closing moment, Ferris pops out from the bathroom to address the audience directly: > "You're still here? It's over! Go home! Go!" before disappearing back inside.
