- Organization for Economic Cooperation and Development
- Organization for European Economic Cooperation
- Organization for Trade Cooperation
- Organization of African Unity
- Organization of American States
- Organization of Petroleum Exporting Countries
- Organization of Regional Cooperation for Development
- Commonwealth Scientific and Industrial Organization
- East African Industrial Research Organization
- Food and Agriculture Organization
- Intergovernmental Maritime Consultative Organization
- International Organization for Standardization
- International Organization of Employers
- International Civil Aviation Organization
- International Labor Organization
- International Refugee Organization
- International Shipping Organization
- International Trade Organization
- North Atlantic Treaty Organization
- Pan-American Health Organization
- United Nations Organization
- United Nations Educational, Scientific and Cultural Organization
- United Nations Industrial Development Organization
- Warsaw Treaty Organization
- World Health Organization
- World Intellectual Property Organization