REDengine is a game engine developed independently by CD Projekt RED. It was designed exclusively for CD Projekt RED's nonlinear, role-playing video games.

REDengine is portable across 32- and 64-bit software platforms and runs under Microsoft Windows. REDengine was first used in The Witcher 2: Assassins of Kings for Microsoft Windows. REDengine 2, an updated version of REDengine used in The Witcher 2 also runs under Xbox 360[ and both OS X and Linux, however these ports were made using a compatibility layer similar to Wine called eON. REDengine 3 was designed exclusively for a 64-bit software platform, and also runs under PlayStation 4 and Xbox One.