Members of International Organizations

Use the dropdown menu to see the members of each group


The North Atlantic Treaty Organization (NATO) is a military alliance established in 1949. Its membership has grown from 12 countries at its founding (ten West European countries, Canada, and the United States) to 29, including Turkey and many members of the former Soviet Union. NATO may be best known for Article 5 of its treaty, which establishes the principle of “collective defense,” committing members to defend each other if attacked. This principle has allowed NATO to intervene in conflicts many times over the last several decades, including in Afghanistan, the Balkans, and Libya.

United Nations

The United Nations is an international organization dating back to 1945. With 193 member states and two nonmember observer states (the Holy See and the State of Palestine), the United Nations aims to promote international peace and stability, human rights, and economic development. It does so through a variety of agencies, funds, and programs, such as the UN Children’s Fund (UNICEF), the UN Educational, Scientific, and Cultural Organization (UNESCO), the World Bank, the World Health Organization (WHO), and many more. The UN Security Council, one of the institution’s most prominent bodies, focuses on the maintenance of international peace and security. It has ten rotating members and five permanent members: China, France, Russia, the United Kingdom, and the United States.

Members of the UN Security Council meet about Syria at UN headquarters in New York, on April 5, 2017.


The World Trade Organization (WTO) is an international institution that focuses entirely on trade. It was created in 1995, effectively replacing the General Agreement on Tariffs and Trade (GATT), which had been signed in 1947. Its 164 members count on the WTO to manage the rules of international trade and ensure the fair and equitable treatment of all, which it does by conducting negotiations, lowering trade barriers, and settling disputes.


The International Criminal Court (ICC) is a global body that investigates and tries those charged with genocide, war crimes, crimes against humanity, and crimes of aggression. Most countries are party to the Rome Statute, the treaty that created the ICC, although controversy over the ICC’s jurisdiction has led to dozens of countries, including the United States, signing but not ratifying the treaty; one country, Burundi, has even withdrawn. 


The European Union (EU) is a supranational organization established in 1992. Nineteen of its twenty-eight members share a common currency, the euro. The EU’s objectives include the economic, political, and security integration of its members, which it attempts to accomplish by removing trade barriers and allowing the free movement of EU citizens among certain member states. The United Kingdom is currently in negotiations to leave the EU.


The Group of Twenty (G20) is a multilateral forum created in 1999 for officials from the largest advanced and developing economies to jointly address global economic concerns. Its membership covers two-thirds of the global population and over three-fourths of global trade. Through meetings of finance ministers, central bank governors, and heads of government, the G20 coordinates economic policy, although it has no way to enforce decisions.

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