Gabriel Knight 3: Blood of the Sacred, Blood of the Damned is a point-and-click adventure game created by Jane Jensen, developed and published by Sierra Studios, and released for Microsoft Windows in 1999. The sequel to 1995's The Beast Within: A Gabriel Knight Mystery, the game's story focuses on the lives of Gabriel Knight (voiced once again by Tim Curry) and Grace Nakimura as they become involved in a case to track down a kidnapped infant, becoming embroiled in a mystery that involves vampires, the Knights Templar, the Holy Grail, and Jesus within the Languedoc province of France; the story itself is inspired by a real-life treasure conspiracy associated to the area.

Following the previous installment, Sierra opted to render the third game in the series in 3D graphics, with a heightened level of puzzle solving and exploration. Work on development was delayed due to difficulties from the team in adapting to the new rendering engine for the game, with some puzzles that were designed found to be complicated and replaced with a number of new puzzles that Jensen did not approve of but could not have changed. Although Jensen had approved of the actor who portrayed Gabriel in the last game, it was decided that Curry should return, owing to her belief he provided the right personality for the character.

Gabriel Knight 3 was the last game to be made by Sierra prior to the crash of the adventure video game industry. Although not a commercial success, much like its predecessors, it received mainly positive reviews from critics. Praise was given to the story and its setting, along with one of the "best-designed game puzzles" in adventure games, while it was criticized for some of its poor dialogue, Curry's performance, and its transfer to 3D graphics. The game was re-released as part of Sierra's Best Seller Series in 2001, and again for GOG.com, in 2010, and Steam, in 2016.