Hellboy is a 2004 American superhero film based on the Dark Horse Comics character of the same name, created by Mike Mignola. Produced by Revolution Studios, Lawrence Gordon/Lloyd Levin Productions, and Dark Horse Entertainment, and distributed by Revolution and Sony Pictures Releasing's Columbia Pictures, it is the first live-action film in the Hellboy franchise. Directed and written by Guillermo del Toro, the film stars Ron Perlman in the title role, alongside Selma Blair, Jeffrey Tambor, Karel Roden, Rupert Evans, and John Hurt. The film draws inspiration from the debut comic Hellboy: Seed of Destruction. In the film, a charismatic demon-turned-investigator named "Hellboy" works with the secretive Bureau of Paranormal Research and Defense to suppress paranormal threats, when a resurrected sorcerer seeks to make Hellboy fulfill his destiny by triggering the apocalypse.

Hellboy had its premiere at the Mann Village Theater in Los Angeles on March 30, 2004, and was released in the United States on April 2 by Sony Pictures Releasing. The film received generally positive reviews from critics and grossed $99.8 million against a production budget between $60–66 million.

The film was followed by a sequel, Hellboy II: The Golden Army, released by Universal Pictures in 2008, and two reboots by Millennium Media.