Saikano (最終兵器彼女, Saishū Heiki Kanojo?, lit. She, the Ultimate Weapon or My Girlfriend, the Ultimate Weapon) is a manga and anime series by Shin Takahashi, creator of Iihito and Kimi no Kakera. Saikano was originally serialized in Shogakukan's Big Comic Spirits magazine.

A live-action movie adaptation was released in Japan on 28 January 2006 with Aki Maeda starring as Chise.