An OpenGL RTS game engine written in C
Real Time Strategy game engine supporting early Westwood classics
Open source clone of the Age of Empires II engine
Open source FPS/RTS Game
0 A.D. is a free, open-source, cross-platform real-time strategy game.
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
3D-Accelerated open-source DOOM engine
Dungeon Master is a RPG/RTS developed on the BYOND engine.
RTS engine