An intergovernmental organization or international governmental organization (IGO) is an organization composed primarily of sovereign states (referred to as member states), or of other intergovernmental organizations. Intergovernmental organizations are often called international organizations, although that term may also include international nongovernmental organization such as international nonprofit organizations or multinational corporations.
Intergovernmental organizations are an important aspect of public international law. IGOs are established by treaty that acts as a charter creating the group. Treaties are formed when lawful representatives (governments) of several states go through a ratification process, providing the IGO with an international legal personality.
Intergovernmental organizations in a legal sense should be distinguished from simple groupings or coalitions of states, such as the G8 or the Quartet. Such groups or associations have not been founded by a constituent document and exist only as task groups.
Intergovernmental organizations must also be distinguished from treaties. Many treaties (such as the North American Free Trade Agreement, or the General Agreement on Tariffs and Trade before the establishment of the World Trade Organization) do not establish an organization and instead rely purely on the parties for their administration becoming legally recognized as an ad hoc commission. Other treaties have established an administrative apparatus which was not deemed to have been granted international legal personality.