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.

Pierrot Co., Ltd. is a Japanese animation studio established in May 1979 by Yuji Nunokawa, previously an animator and director for Tatsunoko Production. Its headquarters are located in Mitaka, Tokyo. Pierrot is renowned for several worldwide popular anime series, such as Naruto, Bleach, Tokyo Ghoul, Yu Yu Hakusho, Black Clover, Boruto: Naruto Next Generations, Ghost Stories, Great Teacher Onizuka, and Saiyuki.