Larry "Pinto"
Larry is a young and rather innocent freshman at Faber, who wants desperately to pledge a fraternity and adapts easily to life as a Delta. He is perhaps the most wholesome member of the fraternity (besides Kent), a virgin, and waits anxiously to have sexual intercourse for the first time, but is alarmed when he finds that the object of his affection is only 13 years old (despite looking much older). He has an affable charm and wants to experience new things. At the end of the film, we learn that he grows up to write for National Lampoon, the publication that produced the film.
Kent "Flounder"
Kent is the corpulent and kind-hearted friend of Larry. He is a "legacy" at Delta, since his older brother was a member, and he wants very badly to fit in, in spite of having no social credentials whatsoever. In spite of his flaws, he is accepted into the fraternity. Kent is sensitive and doesn't always want to get into trouble as much as his fellow Deltas, but he always winds up having fun when he does, even so.
Otter
Otter is a notorious ladies' man on campus, a pretty boy who spends most of his time trying to bed the latest beautiful woman in his field of vision. He sleeps with both Mandy Pepperidge and Mrs. Wormer, the mates of his two worst enemies, and pays the price when Greg beats him up at the motel. Otter is the most compelling leader of Delta, and when he speaks up and motivates people, they listen.
Boon
Boon is Otter's best friend, a rather cynical senior who struggles to balance college partying with his obligations to his girlfriend, Katy. She wants him to be more mature and prioritize her over the wild parties at his fraternity, but this is easier said than done.
Katy
Katy is Boon's girlfriend. She's a good sport and not nearly as uptight as some of the other girls on campus, but she also resents the fact that Boon spends so much time with his fraternity brothers. Boon's immaturity eventually leads Katy to have an affair with her older professor, Professor Jennings.
Bluto
Bluto is a crazy and unhinged party boy from Delta, a senior in his seventh year who loves to create chaos and start trouble. Some sources say that Bluto was a cross between "Harpo Marx and the Cookie Monster," an almost preverbal indulger and Falstaffian hero, whose greatest gift is his ability to have fun and go wild at a party.
Robert Hoover
Robert Hoover is the most straitlaced of the Delta brothers, eager to keep things in line, even if he too enjoys a good party just like any of them. An expert negotiator, Hoover grows up to become an attorney.
Dean Wormer
Dean Wormer is the rule-loving dean of the college. He loathes the Delta fraternity with a vengeance and sets his sights on taking them down if it's the last thing he does. An easily-rattled man, he plots with Greg Marmalard to punish Delta for their out-of-control antics, and makes a fool of himself along the way.
Greg Marmalard
Greg Marmalard is the president of Omega, the preppy and uptight fraternity on campus. A smug preppie who is saving himself for marriage, Greg resents the Delta brothers with a vengeance that distracts him from the fact that Mandy, his girlfriend, is sleeping with one of them.
Doug Neidermeyer
Doug is the head of the ROTC on campus, and is obsessed with the military precision the organization gives him. There is nothing Doug loves more than barking orders and keeping people in line, and he so abuses Kent, that the Delta brothers get revenge by stealing his horse (and accidentally killing it).
Professor Jennings
Professor Jennings is a failed novelist and professor at the college. He loves smoking pot and intellectualizing, and his more mature ways earn the attraction of Katy, who feels ignored by Boon.
