Varan the Unbelievable, released in Japan as Giant Monster Varan (大怪獣バラン Daikaijū Baran?), is a 1958 Kaiju film directed by Ishirō Honda (drama) and Eiji Tsuburaya (special effects), and their last black-and-white monster film. The title character Varan is one of Toho Studios' least-famed creations. Although shown in Japanese-language theaters in the USA, the film saw general U.S. release in 1962 only after being heavily revised, in the manner of Godzilla, King of the Monsters!, to have all principal scenes reshot with American actors. Indeed, the plot itself was generally revised, and the Japanese material consisted only of special effects, a few incidental shots, and the ending scene.

Originally, the film was to be produced for American television, but the American producers backed out at the last minute. With most of the film already completed, Toho's crew filmed additional scenes, and it was released in Japanese theaters, but not before adapting the remaining spherical footage from the original production to anamorphic widescreen using a one-shot, SuperScope-like process called TohoPanScope. A reconstruction of the TV version is included on both the Japanese and American DVDs.

The 2005 subtitled DVD release of Daikaijū Baran, the original Japanese version, was titled Varan the Unbelievable on the front cover leading to confusion as to which version of the film (Japanese or American) was presented on the disc.