'Kaiju' is the Japanese word for both giant monsters and the giant monster genre, which may also feature mecha. Toho Studios kaiju include Godzilla, King of the Monsters, Rodan, Ghidora, Mothra, and Angilas. Daiei Studios kaiju include Gamera, Gaos, and Viras. Non-Japanese kaiju include Gorgo and perhaps King Kong, though some kaiju fans insist that only costumed actors qualify, not stop-motion animation nor computer graphics.

See sentai, tokusatsu and manga/anime.