Gamera (大怪獣ガメラ Daikaijū Gamera?, Giant Monster Gamera, released in the United States as Gammera the Invincible(spelled with 2 m's) and in 2010 on DVD as Gamera: The Giant Monster) is a 1965 Science fiction Kaiju film directed by Noriaki Yuasa. The film's plot involves an ancient giant turtle monster called "Gamera" who has been unleashed from its icy tomb by an atom bomb only to terrorize the entire country of Japan.

The film is the first in a series of Kaiju (giant monster) films featuring the monster Gamera. Though created to capitalize on the success of Toho's popular Godzilla films, Gamera did manage to find success on its own and spawn its own franchise. After several sequels over the years, fans have widely regarded Gamera as one of Japan's most memorable Kaiju characters, right behind Godzilla. It was one of five Gamera films to be featured on the movie-mocking television show Mystery Science Theater 3000.