The Doom engine, also known as id Tech 1, is the game engine that powers the id Software games Doom and Doom II: Hell on Earth. It is also used in Heretic, , Strife: Quest for the Sigil, Hacx: Twitch 'n Kill, Freedoom, and other games produced by licensees. It was created by John Carmack, with auxiliary functions written by Mike Abrash, John Romero, Dave Taylor, and Paul Radek. Originally developed on NeXT computers, it was ported to DOS for Doom's initial release and was later ported to several game consoles and operating systems.

id Tech is a series of separate game engines designed and developed by id Software. Prior to the presentation of the id Tech 5-based game Rage, the engines lacked official designation and as such were simply referred to as the Doom and Quake engines, from the name of the main game series the engines have been developed for. "id Tech" numbers 2, 3, and 4 have been released as free software under the GNU General Public License, along with the source code to Wolfenstein 3D, Doom, and Quake.

Id tech may refer to:

• Identification Technology Partners, Inc., an engineering and consulting firm in Gaithersburg, Maryland
• International Display Technology, an IBM/Chi Mei partnership sold to Sony in 2005
• id Tech, a series of game engines developed by id Software
• Internal Drive, a computer camp, also referred to as "iD"

iD Tech Camps (commonly referred to as iD Tech or Internal Drive) is a summer computer camp based in Campbell, California, which specializes in providing computer technology education to children ages 6 through 18. It currently offers programs at over 100 university, college, high school, and elementary school locations throughout the United States.