Kimi wa Girlfriend is about a girl named Hatsune with a "bad mouth," for lack of a better description. She's kind-hearted, but her mouth spews the total opposite of what she means (which is probably due to the fact that she grew up with only male influence). Thus, she is seen as an arrogant, vulgar girl at her school, but all she wants is a boyfriend. Well, that is, until she gets accepted at the Maidens' Club, where she meets a guy named Kirie, with a somewhat unique habit that happens when a girl comes within a foot of him. Everyone says he's gay, even Hatsune.

How will these two fare? Will Hatsune have a boyfriend at last? Will he be more than just a friend?