Zone Fighter, known in Japan as Ryūsei Ningen Zone, is a tokusatsu science fiction superhero television series. Produced by Toho Company Ltd., the show aired on Nippon Television from April 2 to September 24, 1973, with a total of 26 episodes, it was cancelled due to the oil crisis of 1973. This was Toho's answer to not only the popular Ultra Series, but the Henshin Hero phenomenon started by shows like Kamen Rider and Android Kikaider. The previous year, Toho had just made their successful first superhero show, Rainbowman. The series was also notable for its guest appearance by Toho's own Godzilla, as well as two other Toho monsters, King Ghidorah and Gigan. Supplementary materials published by Toho have confirmed Zone Fighter to be part of the Showa-era Godzilla series, taking place in between Godzilla vs. Megalon and Godzilla vs. Mechagodzilla.

A série gira em torno de uma família vinda do espaço sideral chamada Família Zone. Ao procurarem refúgio na Terra, eles se disfarçam de seres humanos sob a identidade da família Sakimori. Porém, não demora muito para eles serem perseguidos pelo Império Garoga. Para combater essa ameaça, os três filhos da Família Zone – Hikaru, Hotaru e Akira – se transformam em Zone Fighter, Zone Angel e Zone Junior para combater por igual os monstros gigantes de Garoga. Hikaru, o Zone Fighter, é o único dos três irmãos capaz de ficar gigante também.