Fey, 33, said "Queen Bees & Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends and Other Realities of Adolescence" inspired the film and reminded her of her own high school days, ABC reported Friday.
It's amazing, she said, "that girls somehow at a certain age know how to screw with each other. ... It all rang true to me."
The film stars Lindsay Lohan as a homeschooled teen who grew up in Africa, leaving her unprepared for the backstabbing prima donnas she found in a metropolitan high school.
Fey also co-stars in "Mean Girls," which opens Friday in U.S. theaters.