Endless Sky is a sandbox-style space exploration game
Real Time Strategy game engine supporting early Westwood classics
RTS game with the theme of Strategy by Design
Seven Kingdoms: Ancient Adversaries
Arianne is an engine to develop multiplayer online games like Stendhal
A 2D Real Time Strategy space combat game.
Cross-platform, GPL reimplementation of the classic : Syndicate
Open source FPS/RTS Game
Cross-platform real-time strategy game (3D)
A free 3d game for PC that does not limit the player. Fight,Build,Gain
War of seventh kings
Utilities to make running a MegaMek server easier
Online War system for IL-2 Sturmovik and Iron Front in ArmA 2
0 A.D. is a free, open-source, cross-platform real-time strategy game.
Lines a game written in Python two players through internet
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
RTSish Game Engine
Open RealStrategyGameLibrary (Engine)
A suite of tools to make operating a Empire server easier
An approach where computer solves problems like a human brain does;
WeComeInPeace is a simple RTS game that aims towards multiplayer