The Beast Within: A Gabriel Knight Mystery (also known as Gabriel Knight 2: The Beast Within) is a point-and-click adventure game, created by Jane Jensen, developed and published by Sierra On-Line, and released for MS-DOS, Macintosh, and Microsoft Windows, in 1995. The sequel to 1993's Gabriel Knight: Sins of the Fathers, the game's story focuses on a new investigation for Gabriel Knight, adjusting to his new life as a "shadow hunter", as he investigates a spate of killing around Munich believed to be the work of a werewolf, with assistance in his work from Grace Nakimura, who looks into a link between the killings and the final years of a Bavarian king in the 19th century.

Unlike its predecessor, the game was designed like an interactive movie, produced entirely in full-motion video – a technology that was popular at the time for game production but expensive to use – with computer-generated scenery used for locations in the game, and a strict filming and voice-over schedule. In addition, the involvement of live-action scenes required a recasting of the main characters, with Dean Erickson and Joanne Takahashi portraying the lead roles, both of whom are playable during the story at different intervals.

The Beast Within garnered critical praise for its storytelling and characterization, as well as its presentation, but was not a commercial success as Jensen hoped for. Despite this, it received a sequel, Gabriel Knight 3: Blood of the Sacred, Blood of the Damned, in 1999.