Mazinkaiser (マジンカイザー, Majinkaizā) is a Japanese anime OVA produced by Brain's Base and Dynamic Productions, based on the Mazinkaiser design that debuted in Super Robot Wars games and the original Mazinger Z manga by Go Nagai. The OVA follows Kouji Kabuto, Tetsuya Tsurugi and the rest of the "Mazinger Team" as they fight against Dr. Hell's Mechanical Beasts while Kouji stumbles upon a forgotten laboratory where he finds Mazinkaiser, the most powerful robot ever built. The series chronicles Kouji's experience with the machine as he copes with Kaiser's power while defeating Dr. Hell's forces.

The OVA series was directed by Masahiko Murata (Jinki: Extend, Corpse Princess) and written by Satoru Nishizono and Shinzo Fujita. It was first released on Japan through Home Video from September 25, 2001 to September 25, 2002 with a total of 7 episodes. An epilogue movie titled Mazinkaiser vs. The Great General of Darkness was released in theaters on July 25, 2003. Mazinkaiser emulates Go Nagai's character designs, and its operatic plot is supported by a "tongue-in-cheek" cynicism in regard to the gratuitous sex and violence. Some of the episodes draw their plot elements from the manga itself rather than the TV series. ADV Films once licensed the series in English territories until the company's closure in 2009.