Cromartie High School (Japanese: 魁!!クロマティ高校, Hepburn: Sakigake!! Kuromati Kōkō, lit. "Forging Valiantly Ahead!! Cromartie High School") is a Japanese manga series written and illustrated by Eiji Nonaka. It was serialized in Kodansha's shōnen manga magazine Weekly Shōnen Magazine from August 2000 to May 2006, with its chapters collected in 18 tankōbon volumes. It follows the everyday life of Takashi Kamiyama and his odd classmates at Cromartie High School, an infamous school for delinquents. The series is a parody of Japanese yankii manga of the 1970s and 1980s. The style of art resembles Ryoichi Ikegami's works such as Otoko-gumi and Otoko Ōzora.

Both the manga and anime have been released in North America by ADV Manga and ADV Films, respectively. However, the manga was not completely published in North America due to restructuring issues at ADV. Discotek Media has since licensed the anime, after ADV's closing in 2009. The series aired in the United States on the cable network G4 on its Barbed Wire Biscuit late-night block and on the UK satellite channel Rockworld TV. It was followed by a spin-off sequel titled Cromartie Kōkō Shokuinshitsu in 2018, launched on Kodansha's Magazine Pocket app.

Cromartie High School has had over 4.5 million copies in circulation. The manga won the 26th Kodansha Manga Award for the shōnen category in 2002.