Katawa Shoujo is a bishoujo-style visual novel set in the fictional Yamaku High School for disabled children, located somewhere in modern Japan. Hisao Nakai, a normal boy living a normal life, has his life turned upside down when a congenital heart defect forces him to move to a new school after a long hospitalization. Despite his difficulties, Hisao is able to find friends—and perhaps love, if he plays his cards right. There are five main paths corresponding to the 5 main female characters, each path following the storyline pertaining to that character.

The story is told through the perspective of the main character, using a first person narrative. The game uses a traditional text and sprite-based visual novel model with an ADV text box.