I'm In Love With My Brother's Best Friend?! is based on the novel published by Tapas Entertainment, Inc.

In I'm In Love With My Brother's Best Friend movie: when Kaitlyn Sinclair moves into her off campus apartment with her high school sweetheart for her freshman year of college, she immediately catches him cheating on her. She is forced to move into her brother’s apartment and share a space with his best friend who is in grad school on the same campus. When her childhood crush reignites, Kaitlyn and Cole must navigate their newfound adult relationship while evil exes, mean girls, and worst of all- Kaitlyn’s brother, try to tear them apart.