id Software LLC is an American video game developer headquartered in Dallas, Texas. The company was founded on February 1, 1991, by four members of the computer company Softdisk, programmers John Carmack and John Romero, game designer Tom Hall, and artist Adrian Carmack Business manager Jay Wilbur was also involved.

id Software made important technological developments in video game technologies for the PC (running MS-DOS and Windows), including work done for the Wolfenstein, Doom, and Quake franchises. id's work was particularly important in 3D computer graphics technology and in game engines that are heavily used throughout the video game industry.

The company was also heavily involved in the creation of the first-person shooter genre. Wolfenstein 3D is often considered as the first true FPS, Doom was a game that popularized the genre and PC gaming in general, and Quake was id's first true 3D first-person shooter.