Not all games distributed by Valve are compatible with Garry's Mod; only games that take advantage of Source's physics engine are supported. Here's a list (as of Garry's Mod 13): Edit

  • Age of Chivalry (Free on Steam)
  • Alien Swarm (Free on Steam)
  • Blade Symphony(Free on Steam)
  • Counter-Strike: Source
  • Counter Strike: Global Offensive (Free on Steam)
  • D.I.P.R.I.P. Warm Up (Free on Steam)
  • Day of Defeat: Source
  • Dino D-Day
  • Dystopia (Free on Steam)
  • Fistful of Frags (Free on Steam)
  • Half-Life 2 (Half-Life: Source, Half-Life 2: Deathmatch, Half-Life Deathmatch: Source, Half-Life 2: Lost Coast, Half-Life 2: Episode One, Half-Life 2: Episode Two are also supported)
  • Insurgency (Source Mod)
  • Left 4 Dead 1 & 2
  • Nuclear Dawn
  • Pirates, Vikings, and Knights II (Free on Steam)
  • Portal 1 & 2
  • The Stanley Parable
  • Team Fortress 2 (Free on Steam)
  • Zeno Clash
  • Zombie Panic: Source (Free on Steam)
  1. Note that Garry's Mod no longer requires any other game to play, you can purchase just the game and be set, but if you have the space for the free games, they will help add more content.
  2. When viewing a game in the Steam Store, all games that support Garry's Mod will say: Includes Source SDK. It is required that games contain the SDK as that allows Garry's Mod to use its resources.
  3. Make sure you run each game at least once, simply installing the game isn't always enough, extra things may be downloaded with the first time you run it. The demos for Half-Life 2, Zeno Clash and Portal (subtitled with First Slice) are free and still add some content.
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