Duke Nukem 3D is a first-person shooter developed by 3D Realms and released on January 29, 1996 by Apogee Games, featuring the adventures of Duke Nukem, loosely based on a character that had appeared in earlier platform games by the company, Duke Nukem and Duke Nukem 2.

The game was mainly notable for the (often crude) humor it introduced into what had previously been a fairly humorless genre, including a stream of one-liners from the title character. For instance, when the player comes upon a corpse that closely resembles the player character in DOOM, Duke comments, "That's one doomed space marine." That quote became famous after sites dedicated to Duke Nukem 3D began reporting that id Software filed a lawsuit against Apogee Games and 3D Realms for that quote, trying to obtain an injunction to have that removed, but was unsuccessful.

The game also featured some of the most varied weapons in any first-person shooter game, including a shrink ray.

The game freely plundered many themes, such as the Alien film series and the film Army of Darkness.

The source code to the Duke Nukem 3D executable was released under the GPL in April 2003. However, the game content still remains the sole property of 3D Realms.

A long-promised sequel, Duke Nukem Forever, is still in production after several years of development.