Godzilla is the English name for the monster Gojira (Toho, 1954). This was the first of many "giant monster" movies (known as kaiju) to be produced in Japan starting in the 1950s, and movie fans still consider it to be one of the best.

Filmed in stark black and white, Gojira tells the story of a giant, terrifying, fire-breathing monster who is disturbed by American atom bomb testing in the Pacific Ocean. The monster attacks a number of ships and makes a brief land appearance, before coming ashore in Tokyo, Japan and destroying the entire city during an unstoppable rampage. Emiko Yemane pleads for Dr. Serizawa to use the secret weapon. A few minutes later, Dr. Serizawa burned all his notes and said that he would use the secret weapon but no one in the future could ever know about "the Oxygen Destroyer." The monster is finally defeated when a Japanese scientist (Takashi Shimura) uses an experimental underwater weapon (the Oxygen Destroyer) to destroy it. The scientist intentionally sacrifices his life while destroying Gojira, because he believes his invention is too terrible to be used by humanity.

The monster Gojira is widely seen as an allegory for the atomic bomb: an unstoppable force, powered by radiation, that lays waste to Japan in a manner similar to what occurred in World War II, or simply America as a threatening nuclear power; this movie was made only nine years after Japan's defeat, and only a few months after the Castle Bravo nuclear testing accident which had a great psychological impact on Japanese society. Unlike later movies in the "giant monster" genre, Gojira was filmed in a completely serious manner, and it has lost little of its power in the years since. Ishiro Honda, the director, was a second-unit director on several of Akira Kurosawa's films, and his stark black-and-white cinematography seems more realistic, harsh, and terrifying than many of the later color Godzilla movies.

Gojira was released in the United States under the title Godzilla, King of the Monsters, and the giant monster would be known by the name Godzilla ever after. Several minutes' worth of footage were deleted from the American version of the film, and new footage of the actor Raymond Burr was inserted into the film, presumably so that American audiences would have an American hero to identify with.

The film was directed by Ishiro Honda and had special effects by Eiji Tsuburaya.