The movie, which is set in Seattle, Washington, features John Cusack as Lloyd Dobler, an average student and aspiring kickboxer who improbably attempts a relationship with school valedictorian Diane Court (played by Ione Skye), despite the fact that some of his friends believe she is out of his league. Diane falls for Lloyd, partly because of his gallant ways and partly because he makes her laugh. However, their relationship is beset by several obstacles. Diane has just won a major scholarship to study in England and will be going there at the end of the summer. Her father James, played by John Mahoney, is under investigation by the Internal Revenue Service for alleged tax violations committed at his nursing home, and Diane worries she should be spending more time with her father rather than Lloyd. Also, Diane's father does not approve of his daughter dating an underachiever like Lloyd, and pressures her to break up with him, which she reluctantly does. Lloyd ultimately wins her heart before the summer's end and helps support Diane through her father's conviction. The film ends with Lloyd escorting nervous-flyer Diane to England.

In the movie's most famous scene, Lloyd appears outside Diane's bedroom window carrying a boombox over his head playing Peter Gabriel's "In Your Eyes". The scene has become well-known in pop culture and is a frequently used reference in TV and film.