Duke Nukem 3D is a 1996 first-person shooter game developed by 3D Realms and published by FormGen for MS-DOS. It is a sequel to the platform games Duke Nukem and Duke Nukem II, published by 3D Realms.

Duke Nukem 3D features the adventures of the titular Duke Nukem, voiced by Jon St. John, who fights against an alien invasion on Earth. Along with Wolfenstein 3D, Doom and Quake, Duke Nukem 3D is considered to be responsible for popularizing first-person shooters, and was released to major critical acclaim. Reviewers praised the interactivity of the environments, gameplay, level design, and unique risqué humor, a mix of pop-culture satire and lampooning of over-the-top Hollywood action heroes. However, it also incited controversy due to its violence, erotic elements, and portrayal of women.

The shareware version of the game was originally released on January 29, 1996, while the full version of the game was released on April 19, 1996. The Plutonium PAK, an expansion pack which updated the game to version 1.4 and added a fourth eleven-level episode, was released on October 21, 1996. The Atomic Edition, a standalone version of the game that included the content from the Plutonium PAK and updated the game to version 1.5, was released on December 11, 1996. An official fifth episode was released on October 11, 2016, with 20th Anniversary World Tour published by Gearbox Software. A direct sequel titled Duke Nukem Forever was released in 2011, after fifteen years in development hell.