id Tech 2 refers to either of the following game engines developed by id Software which were retroactively renamed:

• Quake engine
• QuakeWorld Engine
• Quake II engine

id Tech 2, popularly known as the Quake II engine, upgraded from  Quake engine, is a game engine developed by id Software for use in their games, most notably Quake II. Since its release, the Quake II engine has been licensed for use in several other games.