The term intergovernmental organization (IGO) refers to an entity created by treaty, involving two or more nations, to work in good faith, on issues of common interest. In the absence of a treaty an IGO does not exist in the legal sense. For example, the G8 is a group of eight nations that have annual economic and political summits. IGOs that are formed by treaties are more advantageous than a mere grouping of nations because they are subject to international law and have the ability to enter into enforceable agreements among themselves or with states.
The main purposes of IGOs were to create a mechanism for the world's inhabitants to work more successfully together in the areas of peace and security, and also to deal with economic and social questions. In this current era of increasing globalization and interdependence of nations, IGOs have come to play a very significant role in international political systems and global governance.
These are some key organizatons: