Van Wilder is a guy who has been at his college for seven years. He spends most of his time throwing parties and "fund raisers". When his father decides that it's time for tough love, he doesn't pay his tuition. So Van becomes a professional party thrower. At the same time, Gwen who writes for the college paper, is tasked with doing a story on him, but Van is too busy partying to do that. So she writes it using info from people who talk about him and writes an unflattering piece, which doesn't make him happy. He then dares her to see if she can get the true story but is more interested in trying to score with her, which is not easy because she has a boyfriend, who is a snob, and who is not too happy with the amount time she is spending with him. So he tries to get rid of him.

In the Midwest of USA, the sweethearts Drew and Julia are graduating in the college. Drew convinces Julia to move with him to Los Angeles, where his sister Terri lives and got a job for him. The young couple become close friends of their neighbors Elyse and Lenny Steinberg, who owns a small real estate business. However, the immature Drew breaks the relationship with Julia, afraid of the consequences of their commitment.

For newlyweds Carl and Molly Peterson, life can't get any sweeter as they begin anew to settle down into married life. With a nice house and established careers in tow, nothing seems to get in their way. However, Carl is about find out just how much friendship means when Dupree, his best friend has been displaced from his home and fired from his job because of attending their wedding. Taking his friend in, what Carl and Molly are about to experience is that the fine line between a few days and whatever else is after, can be a lot more than they bargained for. Especially when their friend overstays his welcome in far too many ways than he should.