| Academy Of European Law | ERA | 1992 | Germany | era.int |
| Advisory Centre On World Trade Organization Law | ACWL | 1999 | Seattle | www.acwl.ch |
| African Development Bank | AfDB | 1964 | Abidjan, Cote D’Ivoire | www.afdb.org |
| African Union | AU | 1963 | Addis Ababa, Ethiopia | au.int |
| Agency For International Trade Information And Cooperation | AITIC | 2002 | | |
| Agreement On The Conservation Of Albatrosses And Petrels | ACAP | 2004 | Hobart, Tasmania, Australia | acap.aq |
| Alliance For Financial Inclusion | AFI | 2008 | Kuala Lumpur, Malaysia | |
| Antarctic Treaty Secretariat | ATS | 2004 | Buenos Aires, Argentina | www.ats.aq |
| Arab League | | 1945 | Caracas, Venezuela | www.LasPortal.org |
| Arab Maghreb Union | AMU | 1989 | Rabat, Morocco | www.maghrebarabe.org/en |
| Asia Cooperation Dialogue | ACD | 2002 | | www.acd-dialogue.org |
| Asia Pacific Economic Cooperation | APEC | 1989 | Singapore | www.apec.org |
| Asia-Europe Foundation | ASEF | 1997 | Singapore | www.ASEF.org |
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| Asian Development Bank | ADB | 1966 | Ortigas Center Mandaluyong,
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| Asian Infrastructure Investment Bank | AIIB | 2016 | Beijing, China | www.aiib.org |
| Assembly Of European Regions | AER | 1985 | | aer.eu |
| Association Of Caribbean States | ACS | 1994 | Port-of-Spain, Trinidad And Tobago | www.acs-aec.org |
| Association Of Southeast Asian Nations | ASEAN | 1967 | Jakarta, Indonesia | ASEAN.org |
| Australia, New Zealand, United States Security Treaty | ANZUS | 1951 | | |
| Baltic Marine Environment Protection Commission | HELCOM | 1974 | Helsinki, Finland | www.helcom.fi |
| Bank For International Settlements | BIS | 1930 | Basel, Switzerland | www.bis.org |
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| Black Sea Trade And Development Bank | BSTDB | 1997 | Thessaloniki, Greece | www.bstdb.org |
| Bolivarian Alliance For The Americas | ALBA | 2004 | Caracas | www.portalalba.org |
| British–Irish Council | BIC | 1999 | Edinburgh, Scotland | britishirishcouncil.org |
| Caribbean Community | CARICOM | 1973 | Georgetown, Guyana | CARICOM.org |
| Caribbean Development Bank | CDB | 1969 | Wildey | |
| Central American Bank For Economic Integration | CABEI | 1960 | Tegucigalpa, San Salvador | www.bcie.org |
| Central American Integration System | SICA | 1907 | | sica.int |
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| Central European Initiative | CEI | 1989 | Trieste | www.cei.int |
| Central Treaty Organization | CENTO | 1955 | Ankara | |
| CERN | | 1954 | Meyrin, Canton Of Geneva, Switzerland | home.cern |
| Collective Security Treaty Organization | CSTO | 1992 | Moscow, Russia | odkb-csto.org |
| Commission For The Conservation Of Antarctic Marine Living Resources | CCAMLR | 1980 | Hobart, Australia | www.ccamlr.org |
| Commonwealth Of Independent States | CIS | 1922 | | CIS.Minsk.by |
| Commonwealth Of Learning | COL | 1988 | Metro Vancouver, Canada | www.col.org |
| Commonwealth Of Nations | | 1926 | Marlborough House, London, England, United Kingdom | thecommonwealth.org |
| Community Of Latin American And Caribbean States | CELAC | 2010 | | |
| Community Of Portuguese Language Countries | CPLP | 1996 | Palace Of The Counts Of Penafiel Lisbon, Portugal | www.cplp.org |
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| Conference On Disarmament | CD | 1984 | Palais Des Nations | www.unog.ch |
| Council For Mutual Economic Assistance | Comecon | 1949 | Moscow | |
| Council Of Europe | CoE | 1949 | Strasbourg, France | www.coe.int |
| Council Of Europe Development Bank | CEB | 1956 | Paris | |
| Council Of The Baltic Sea States | CBSS | 1992 | Stockholm, Sweden | www.cbss.org |
| East African Community | EAC | 1967 | Arusha | www.eac.int |
| Economic Community Of Central African States | ECCAS | 1983 | | ceeac-eccas.org |
| Economic Community Of West African States | ECOWAS | 1975 | Abuja, Nigeria | www.ecowas.int |
| Economic Cooperation Organization | ECO | 1964 | Tehran, Iran | www.eco.int |
| Energy Charter Treaty | ECT | 1991 | Brussels, Belgium | www.energycharter.org |
| Energy Community | | 2005 | Vienna, Austria | www.energy-community.org |
| EUCLID (university) | | 2008 | Gambia, Belgium | www.euclid.int |
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| Eurasian Economic Community | EAEC | 2000 | | www.eurasiancommission.org |
| Eurasian Economic Union | EEU Or EAEU | 1994 | Moscow, Russia, Minsk, Belarus | eaeunion.org |
| European Atomic Energy Community | EAEC | 1958 | | |
| European Bank For Reconstruction And Development | EBRD | 1991 | London | ebrd.com |
| European Centre For Medium-range Weather Forecasts | ECMWF | 1975 | Reading, United Kingdom | www.ecmwf.int |
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| European Fusion Development Agreement | EFDA | 1999 | Culham, United Kingdom, Garching, Germany | efda.org |
| European Molecular Biology Laboratory | EMBL | 1974 | Heidelberg | www.embl.org |
| European Organisation For The Exploitation Of Meteorological Satellites | EUMETSAT | 1986 | Darmstadt, Germany | www.eumetsat.int |
| European Organisation For The Safety Of Air Navigation | EUROCONTROL | 1960 | Brussels, Belgium | www.eurocontrol.int |
| European Patent Organisation | EPOrg | 1977 | Munich | www.epo.org |
| European Science Foundation | ESF | 1974 | Strasbourg, France | www.esf.org |
| European Southern Observatory | ESO | 1962 | Garching, Germany | ESO.org |
| European Space Agency | ESA | 1975 | Paris, Île-de-France, France | www.esa.int |
| European Synchrotron Radiation Facility | ESRF | 1994 | Grenoble, France | www.esrf.eu |
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| Food And Agriculture Organization | FAO | 1945 | Palazzo FAO, Rome, Italy | FAO.org |
| Global Environment Facility | GEF | 1992 | Washington DC, United States | www.thegef.org |
| GUAM Organization For Democracy And Economic Development | | 1997 | Kiev, Ukraine | guam-organization.org |
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| Inter-American Tropical Tuna Commission | IATTC | 1949 | La Jolla, San Diego, California, United States | |
| Intergovernmental Authority On Development | IGAD | 1986 | Djibouti City | www.igad.org |
| Intergovernmental Organisation For International Carriage By Rail | OTIF | 1985 | Berne, Switzerland | www.otif.org |
| Intergovernmental Panel On Climate Change | IPCC | 1988 | Geneva, Switzerland | www.ipcc.ch |
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| International Authority For The Ruhr | IAR | 1949 | | |
| International Bank For Reconstruction And Development | IBRD | 1944 | Washington, D.C., United States | worldbank.org/ibrd |
| International Bureau Of Education | IBE-UNESCO | 1925 | Geneva, Switzerland | www.ibe.unesco.org |
| International Bureau Of Weights And Measures | BIPM | 1875 | France | www.bipm.org |
| International Centre For Migration Policy Development | ICMPD | 1993 | Vienna | icmpd.org |
| International Centre For Settlement Of Investment Disputes | ICSID | 1966 | Washington, D.C., United States | icsid.worldbank.org |
| International Centre For The Study Of The Preservation And Restoration Of Cultural Property | ICCROM | 1956 | Rome, Italy | www.iccrom.org |
| International Civil Aviation Organization | ICAO | 1947 | Montreal, Quebec, Canada | www.icao.int |
| International Commission For The Conservation Of Atlantic Tunas | ICCAT | 1969 | Rio De Janeiro, Brazil | www.iccat.int |
| International Commission On Civil Status | ICCS | 1948 | Secretariat General | ciec1.org |
| International Commission On Missing Persons | ICMP | 1996 | The Hague | www.icmp.int |
| International Cospas-Sarsat Programme | | 1988 | Montreal, Quebec, Canada | www.cospas-sarsat.int |
| International Council For The Exploration Of The Sea | ICES | 1902 | Copenhagen, Denmark | www.ices.dk |
| International Criminal Court | ICC | 1998 | The Hague, Netherlands | www.icc-cpi.int |
| International Criminal Police Organization | Interpol | 1923 | Lyon, France | www.interpol.int |
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| International Development Law Organization | IDLO | 1983 | Rome, Italy | idlo.int |
| International Energy Agency | IEA | 1974 | Paris, France | www.iea.org |
| International Energy Forum | IEF | 1991 | Riyadh, Saudi Arabia | www.ief.org |
| International Finance Corporation | IFC | 1956 | Washington, DC | ifc.org |
| International Fund For Agricultural Development | IFAD | 1977 | Rome, Italy | www.ifad.org |
| International Hydrographic Organization | IHO | 1921 | Monaco | www.iho.int |
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| International Institute For Democracy And Electoral Assistance | International IDEA | 1990 | Stockholm, Sweden | www.idea.int |
| International Institute For The Unification Of Private Law | UNIDROIT | | Rome, Italy | www.unidroit.org |
| International Labour Organization | ILO | 1919 | Geneva, Switzerland | www.ilo.org |
| International Maritime Organization | IMO | 1959 | London, United Kingdom | www.imo.org |
| International Monetary Fund | IMF | 1945 | Washington, D.C., U.S. | imf.org |
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| International Organization For Migration | IOM | 1951 | Geneva, Switzerland | www.iom.int |
| International Organization Of Turkic Culture | TÜRKSOY | 1993 | Ankara, Turkey | www.turksoy.org |
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| World Food Programme | WFP | 1963 | Rome, Italy | www.wfp.org |
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| World Trade Organization | WTO | 1995 | Centre William Rappard, Geneva, Switzerland | www.wto.org |