Gary Holian is an American author of several products and articles for the Dungeons & Dragons role playing game, especially for the World of Greyhawk campaign setting. He also runs the Greytalk electronic mailing list and the Canonfire! website about the Greyhawk setting.
Holian has authored or co-authored several works, including the Living Greyhawk Gazetteer, the Dungeons & Dragons Gazetteer, and articles for Dragon, Dungeon, the Living Greyhawk Journal, and Polyhedron.