The World
The UN Treaty Collection
This collection includes all types of treaties from all nations from 1945 to the present. Online access is free and does not require any login. If there are several different copies of a treaty, the one from this collection is the one that should be cited.
The League of Nations Treaty Collection
This collection ranges from 1920 to 1946. Like its successor above, it includes all types of treaties from all members of the League during that period.
World Treaty Library
This collection includes both of the above and many, many more smaller treaty collections from 1648 to the present.
Africa
African Multilateral Organizations, Treaties, Conventions and Declarations
This is a selective database of full-text African multilateral treaties produced by the Department of International Relations & Cooperation of the Republic of South Africa.
OAU/AU Treaties, Conventions, Protocols, & Charters
Asia
Association of Southeast Asian Nations (ASEAN)
There is no one comprehensive ASEAN list or database of treaties; they can be found in each division of the website.
Europe
Council of Eur., Complete List of the Council of Europe’s Treaties
Eur-Lex: Access to European Union Law
This includes both the treaties that formed the Communities and the Union as well as treaties between the Union and states outside the Union such as the US.
Latin America
Organization of American States Treaty Series
Includes all treaties promulgated under the auspices of the OAS from 1947 to the present.