There are more than 300 intergovernmental organizations around the world. The United Nations (UN) is the largest and most familiar intergovernmental organization. In 1945, at the end of World War II, governments wanted to avoid future wars. They formed the UN.

What Is the Largest Human Organization in the World? The United Nations (UN), an international body with 193 member states committed to advancing world peace, cooperation, and development, is the biggest human organization in the world.

Examples include the United Nations; NATO (North Atlantic Treaty Organization); OAS (Organization of American States); APEC (Asia-Pacific Economic Cooperation); ASEAN (Association of South East Asian Nations); and the WTO (World Trade Organization).

Other well-known IGOs are the European Union (EU), the Organization of Petroleum Exporting Countries (OPEC), the African Development Bank (ADB) and the World Trade Organization (WTO). Since the creation of the UN and NATO, IGOs have become essential actors in the international community.