Kiss×sis (キス×シス, Kisu×shisu?) is a Japanese seinen manga written and illustrated by Bow Ditama. The manga originally was printed as a one-shot in January 2004 in Kodansha's seinen manga magazine Bessatsu Young Magazine, and began regular serialization in the same magazine on December 11, 2005. As of November 2008, five tankōbon volumes of the manga have been released in Japan. An original video animation episode by Feel was bundled with the third manga volume released on December 22, 2008. A TV anime series adaptation produced an "alternate retelling" from the OVAs was announced on November 13, 2009.

PLOT:
Kiss×sis's story begins with Keita Suminoe, a male third-year junior-high school student studying for his high school entrance exams. He is living in a home with his older twin stepsisters, Ako and Riko, who kiss, flash, and display their love for him in public. They help him prepare for his exams. Although they share no blood-relation to him, Keita begins to become romantically attracted to his two stepsisters and initially dislikes himself for it. Seeing this attraction, his two parents encourage him to eventually get married to one of them.