“- Dr. Lilian Thurman: Do you still think about girls a lot? How are things going at school?
- Donnie Darko: I think about girls a lot.
- Dr. Lilian Thurman: I asked you about school, Donnie.
- Donnie Darko: I think about fucking a lot during school.”
Katharine Ross - Dr. Lilian Thurman
Jake Gyllenhaal - Donnie Darko

“Go to bed. You have a geography test in the morning.”

Cher - Cher

“Ah, you college men are all alike: all you think about is getting laid! I almost wish I was enrolling in school with you guys!”
James Cromwell - Mr. Skolnick

“- Thornton Melon: What's your favorite subject?
- Bubbles the Hot Tub Girl: Poetry.
- Thornton Melon: Really? Well, maybe you can help me straighten out my Longfellow.”
Rodney Dangerfield - Thornton Melon
Becky LeBeau - Bubbles the Hot Tub Girl

“- Albert Rosenfeld: Tell me some other things about her.
- Special Agent Dale Cooper: She's in high school. She is sexually active. She is using drugs. She's crying out for help.
- Albert Rosenfeld: Well damn, Cooper, that really narrows it down. You're talking about half the high school girls in America!”

Miguel Ferrer - Albert Rosenfeld
Kyle MacLachlan - Special Agent Dale Cooper