Steel Jeeg (鋼鉄ジーグ, Kōtetsu Jīgu), also known as Kotetsu Jeeg or Koutetsu Jeeg, is a Japanese mecha anime series created by manga artists Go Nagai and Tatsuya Yasuda and produced by Toei Doga (now Toei Animation), directed by Masayuki Akehi. It was first broadcast on NET in Japan from October 5, 1975, to August 29, 1976, lasting for 46 episodes. Steel Jeeg also ran as a manga in several children's publications, with the original manga was first serialized in Kodansha's TV Magazine from August 1975 to June 1976.

The series is the first installment in Takara's Magne-Robo franchise, which later became its own series after the rights of the show were passed to Dynamic Productions. A sequel series called Kotetsushin Jeeg aired on the satellite network WOWOW, beginning April 5, 2007.