Under the Chatham House Rule, anyone who comes to a meeting is free to use information from the discussion, but is not allowed to reveal who made any particular comment. It is designed to increase openness of discussion. The rule is a system for holding debates and discussion panels on controversial topics, named after the London headquarters of the Royal Institute of International Affairs, where the rule originated in June 1927.

The Royal Institute of International Affairs, commonly known as Chatham House, is a British think tank based in London, England. Its stated mission is "to help governments and societies build a sustainably secure, prosperous, and just world". It is the originator of the Chatham House Rule.