Takashi Sorimachi is a Japanese actor and singer. He is mostly famous for having portrayed Eikichi Onizuka in the 1998 live-action drama adaptation of the popular manga series Great Teacher Onizuka, and the assassin O in Hong Kong action thriller film Fulltime Killer.

Great Teacher Onizuka, officially abbreviated as GTO, is a Japanese manga series written and illustrated by Tooru Fujisawa. It was originally serialized in Kodansha's shōnen manga magazine Weekly Shōnen Magazine from January 1997 to February 2002, with its chapters collected in 25 tankōbon volumes. The story focuses on 22-year-old ex-bōsōzoku member Eikichi Onizuka, who becomes a teacher at a private middle school, Holy Forest Academy, in Tokyo, Japan. It is a continuation of Fujisawa's earlier manga series Shonan Junai Gumi and Bad Company, both of which focus on the life of Onizuka before becoming a teacher.