Jonathan Ogner (McCarthy) is a young man from a working-class background who is striving upward. His parents have managed to send him to a snooty prep academy for his senior year of high school. His roommate, Skip Burroughs (Lowe) is from a super-rich family but feels his own pressure, from a domineering father who is pushing him to succeed. After an initial clash Jonathan and Skip become friends.
Skip recommends a club he knows where Jonathan can meet women. Jonathan goes, and meets Ellen (Bisset), who looks to be a good 20 years older than he is but is still gorgeous. Ellen gets the impression that Jonathan is a grad student, Jonathan rolls with that idea, and soon they are having a torrid affair. Eventually, of course, Ellen finds out that her young lover is quite a bit younger than she thought he was.
Then Jonathan finds out that Ellen is Skip's mom.
One of the first films to be associated with the group of '80s actors known as the Brat Pack, specifically McCarthy (in his film debut) and Lowe (in his second movie). Also the film debuts of John Cusack (another student at the prep school), Virginia Madsen (a student at the affiliated girls' prep school) and Lolita Davidovich.
- Boarding School: A snooty boarding school where the young men seem to be mostly rich, and mostly preoccupied with drinking and smoking dope.
- Chekhov's Gun: Early in the film Jonathan idly comments that the worst thing he's ever done is to cheat on the SATs, so he could get into Harvard. In the third act of the film a detective from the State Attorney's office comes to campus to investigate—theft of SATs.
- Coming of Age Story: Jonathan has his first adult love affair and comes into maturity.
- Conversation Cut: When warning Jonathan about his unpleasant father, Skip says "If you really want to get on his good side, just tell him you have a hard-on for firm government control." Cut to Franklin in the next scene, in a pompous authoritarian voice, saying "Government control, Jonathan, is anathema to the freedom of our system."
- Elevator Conference: One scene has a "private" moment... in a glass panoramic elevator in Water Tower Place in Chicago.
- Elevator Going Down: On their first meeting, Jonathan and Ellen have sex in a glass elevator.
- Establishing Character Moment:
- When Ellen is first introduced she is in a bar playing a drinking game called "instant margarita" where people pour alcohol in your mouth from two bottles for as long as you can chug it. She's established as a party girl.
- Her husband (Skip's father Franklin) is shown in his first appearance giving Jonathan a hectoring, humorless lecture about how government regulation of business is bad. He's established as a mean, pompous ass.
- Ethnic Menial Labor: The only black person in the movie is the Burroughs's maid. And she's sassy—basically the only thing stopping her from being a Mammy is that she isn't overweight.
- Eyepiece Prank: A variation on this. Jonathan is at a bar when a good-looking woman goes up to him and says she wants to test his "aura". She tells him to roll a quarter down his nose and around his face. Naturally, the rim of the quarter is covered in ink.
- Fanservice Extra: This is why Virginia Madsen is in the movie. She appears in one scene just so Jonathan the stumbling goof can fall over and accidentally rip her top off.
- Gilligan Cut: After Jonathan and Skip get a tongue-lashing from the dean, they talk mock-seriously about how they have to "get responsible". Cut to the two of them in a liquor store buying booze illegally (which Skip does by the simple expediency of offering the store owner $50 for a bottle).
- Gray Rain of Depression: Ellen picks up Jonathan's wallet when it falls out of his coat and discovers his true age (and, as we later find out, that he goes to the same prep school as her son). She immediately bails on a date with Jonathan without saying a word. Cut to Jonathan, hours later on a bench, waiting forlornly in the rain. It gets funnier when Skip drives up to give Jonathan a ride back to school and soaks him with a Roadside Wave.
- Have I Mentioned I Am Sexually Active Today?: Jonathan's protests that he's had sex "lots of times" are wholly unconvincing.
- Lady Drunk: It eventually becomes clear that Ellen has a drinking problem brought on by her emotionally abusive asshole of a husband. In her first scene she's getting drunk in a bar. She drinks a lot of wine at dinner after being shocked to find out that her boyfriend is a high school student. And she calls room service for a bottle of vodka in a moment of despair, after Jonathan is unsympathetic.
- Meet Cute: Ellen takes pity on Jonathan when a woman plays a mean Eyepiece Prank on him at a bar.
- Mrs. Robinson: Ellen doesn't know just how young Jonathan is, but he's obviously at least 15 years younger than her, and she doesn't care.
- National Geographic Nudity: One of the teachers shows some sort of ethnography film with a scene that shows topless African tribeswomen bouncing around. The boys are very upset when their lesson is interrupted.
- One-Word Title: Class
- Sexy Figure Gesture: All the guys in the dorm have found out that Jonathan had sex with an older woman. In chemistry class another student says "How big?", and Jonathan cups his hands in front of his chest in the "big breast" gesture.
- Sympathetic Adulterer: Ellen cheats on her husband, who is a mean, pompous creep.
- Wacky Fratboy Hijinx: The prep school version thereof. Skip plays a prank on Jonathan the Naïve Newcomer in which he convinces Jonathan that it's tradition for seniors to run around the campus in ladies' underwear. They go dashing out of the dorm together, only for Skip to double back inside and lock Jonathan out. Then Jonathan pulls a prank where he pretends to commit suicide only to embarrass a frantic Skip when Skip calls the dean back to their room.