Just One of the Guys (1985)

"She's about to go where no girl has gone before!"

When Terry Griffith loses her high school's writing competition, she's convinced that it's because she's a girl. So Terry decides to change high schools and pose as a boy to prove her point. Her brother, Buddy, helps her pass as a guy so well that she is soon making friends with the boys at school, including the attractive Rick, who becomes her new best friend. But her gender-swapping makes things difficult when she falls in love with him.