Varan the Unbelievable (Japanese: 大怪獣バラン, Hepburn: Daikaijū Baran, lit. 'Giant Monster Varan') is a 1958 Japanese kaiju film directed by Ishirō Honda, with special effects by Eiji Tsuburaya. Produced and distributed by Toho Co., Ltd, it stars Kōzō Nomura, Ayumi Sonoda, and Koreya Senda, with Haruo Nakajima as Varan. In the film, a reporter's investigation into two mysterious deaths in Japan's mountains leads to the discovery of a giant lake monster, wrecking its way towards civilization.

In 1957, Toho was approached by American Broadcasting-Paramount Theatres (AB-PT) to co-produce a new kaiju film for television. It was intended to be a three-part film, each 30 minutes with fade-in/outs for commercial breaks. However, AB-PT collapsed during production and Toho altered the film's status from a television film to a theatrical feature. As a result, the crew faced difficulties and filming lasted 28 days.

The film was theatrically released in Japan on October 14, 1958. A heavily localized version, with new footage starring Myron Healey in the lead, was released in the United States on December 12, 1962 by Crown International as Varan the Unbelievable. Varan would later be briefly featured in Destroy All Monsters.