Van Wilder is not based on a true story. It's a fictional college comedy designed to provide laughs and entertainment. The characters and events are purely imaginative.
Van Wilder, who has been at college way longer than the average student. His story is about his life on campus. He is super popular and acts as a sort of mentor to other students. There are parts where he has to deal with love interests and also problems that come up because he's been at college for so long, like financial issues and what he's actually going to do with his life in the end.
Yes, it is often claimed to be based on a true story. However, like many movies that claim such a thing, there may be elements of exaggeration and fictionalization for the sake of entertainment. The story of Van Wilder might have been inspired by real - life college experiences or characters, but it's not a pure documentary - style retelling.