An international organization is a formal institution or organization requiring membership from at least three states, operates in several states, and whose members establish common rules, held together by a formal agreement. The Union of International Associations (UIA) provides comprehensive, up-to-date, and reliable information on all international associations. It differentiates between the more than 300 international governmental organizations (IGOs) around the world, which are formal international organizations established by governments through intergovernmental agreements; and over 6000 nonstate or non-governmental organizations (NGOs) whose members are associations, individuals, and other non-state actors such as students, tourist, or professional organizations not subject to direct government control. This guide list information on the most important IGOs and links to resources that provide extended lists of IGOs. For detailed searching and lists of International Organizations use the below link for the Yearbook of International Organizations.
Because of their large numbers, this research guide does not list non-governmental organizations. For detailed listings of NGOs you should use the following resources:
There are more than 300 recognized intergovernmental organizations around the world. The following are cited by the United Nations, the largest and most influential intergovernmental organization, as politically significant.
The red asterisk ( * ) indicates organizations that have received a standing invitation to participate as United Nations Observers in the sessions and the work of the UN General Assembly and maintain Permanent Offices at UN Headquarters.
