Thieves' World is a role-playing game supplement published by Chaosium in 1981, based on the Thieves' World series of novels, notable for including rules that allowed its use with nine different fantasy RPG gaming systems:
- Advanced Dungeons And Dragons
- Adventures In Fantasy
- Chivalry And Sorcery
- Dragon Quest
- Dungeons and Dragons
- The Fantasy Trip
- Rune Quest
- Tunnels and Trolls
Thieves' World was one of the first Shared World fantasy settings, set in the city of Sanctuary established in the novels.
- Absurdly-Spacious Sewer: The boxed set stated that the sewers under Sanctuary were large enough for armed troops to pass through them.
- The City Narrows: The Maze is a neighborhood of Sanctuary that is more thoroughly explored in the game guides.
- Percussive Pickpocket: The Game Master's Guide to Sanctuary had a plethora of random encounter tables. A couple of the entries had pickpockets bumping into the PCs in order to steal from them. Other encounters mentioned a NPC bumping into a PC so players wouldn't think that everyone bumping into them was a pickpocket.