| NOFSA | Norsk Forum for Sor-Asia | In Norwegian | → Area studies |
| NOGC | North Oxford Golf Club (www.nogc.co.uk) | In English | → Sport, physical exercises |
| NOGC | National Organization of Girls Club | In English | |
| NOGESO | NOrda Grupo de Esperanto-StudadO | In Esperanto | |
| NoJEF | Norwich Jubilee Esperanto Foundation | In English | → Foundations |
| NOK | Nijemirdum Oudemirdum Kombinatie | In Dutch | → Sport, physical exercises |
| NORTANA | Norwegian Researchers and Teachers Association of North America (www.nortana.net) | In English | → Associations → Education → Language, linguistics, literature |
| NOS | Na Oefening Sterk | In Dutch | → Sport, physical exercises |
| NOVAKA | Nederlandse Vereniging van Ondernemers-Vakhandelaren in Kantoorinrichtingen en Administratiemiddelen | In Dutch | |
| NOVO | Nieuwolda Onder Vrienden Opgericht | In Dutch | → Sport, physical exercises |
| NOW | National Organization for Women | In English | → Feminism |
| NPMB | Nederlandse Piano- en Muziekinstrumentenbond | In Dutch | → Music |
| NPPC | National Pork Producers Council (www.nppc.org) | In English | → Agricultural sciences |
| NRAAO | Northeastern Regional Association of Assessing Officers (www.nraao.org) | In English | → Associations → 332 |
| NRC | Nieuwe Rotterdamse Combinatie | In Dutch | → Sport, physical exercises |
| NREL | National Renewable Energy Laboratory | In English | → Research institutes → Energy economics |
| NRF | National Research Foundation | In English | → Foundations → Mathematics and natural sciences → Applied sciences, technology |
| NRFN | National Federation of Retail Newsagents | In English | → Trade |
| NRK | Nederlandse Rode Kruis | In Dutch | → Medicine |
| NRL | Naval Research Laboratory (www.nrl.navy.mil) | In English | → Research institutes → 359 |
| NRO | Ne-Registara Organizo = ONGs | Organizações Não Governamentais | In Portuguese = NGO | Non-Governmental Organization | In English = NGO | Nichtregierungsorganisation | In German = ANG | Aozadur Nann-Gouarnamantel | In Breton = ONG | Organisation Non Gouvernementale | In French = ONG | Organizzazione non governativa | In Italian = LSM | Lembaga Swadaya Masyarakat | In Indonesian = ONG | Organización non gobernamental | In Galician = GKE | Gobernuz Kanpoko Erakunde | In Basque = ONG | Organización no gubernamental | In Spanish = ΜΚΟ | Μη κυβερνητικές οργανώσεις | In Greek = NNO | Nevládní nezisková organizace | In Czech = ONG | Organització no governamental | In Catalan = ННО | Неурядові неприбуткові організації | In Ukrainian = ONG | Organização não governamental | In Portuguese = NGO | Niet-gouvernementele organisatie | In Dutch = NVO | Nevyriausybinė organizacija | In Lithuanian |
In Esperanto | |
| NRO | Neregistara Organizajo | In Esperanto | |
| NSAI | National Standard Authority of Ireland | In English | → Standardization |
| NSC | Nepal Study Center | In English | → Language, linguistics, literature → Geography, biography, history |
| NSC | Nijkerkse Sport Club | In Dutch | → Sport, physical exercises |
| NSF | Norsk Sosiologforening | In Norwegian | → Sociology |
| NSF | Nordisk Sociologförbund | In Norwegian | → Sociology |
| NSF | Norges Standardiseringsforbund | In Norwegian | → Standardization |
| NSF | National Science Foundation (www.nsf.gov) | In English | → Foundations → Mathematics and natural sciences |
| NSIA | National Security Industrial Association | In English | → Associations → Military engineering |
| NSL | Northrop Space Laboratory | In English | → Research institutes → Astronomy |
| NSO | National Standards Organisation | In English | → Standardization |
| NSTL | National Space Technology Laboratories | In English | → Research institutes → Astronomy → Spaceflight engineering, astronautics |
| NSU | Nederlandse Scheepvaart Unie | In Dutch | → Sport, physical exercises |
| NSV | Nispense Sport Vereniging | In Dutch | → Sport, physical exercises |
| NSV | Noordense Sport Vereniging | In Dutch | → Sport, physical exercises |
| NSV | Nederlandse Sociologische Vereniging | In Dutch | → Sociology |
| NSV | Nederlandse Schoenmakers Vereniging | In Dutch | |
| NTA | Nusa Tenggara Association | In English | → Associations |
| NTA | National Taxidermists Association | In English | → Associations → Zoology |
| NTA | National Tour Association | In English | → Associations |
| NTA | National Trappers Association | In English | → Associations → Fishing, hunting |
| NTA | Netzwerk Technikfolgenabschätzung | In German | → Applied sciences, technology |
| NTA | National Technology Alliance | In English | → Engineering, technology |
| NTA | National Tax Association | In English | → Associations → Taxes, duties |
| NTA | National Tutoring Association | In English | → Associations → Education |
| NTA | National Technical Association | In English | → Associations → Applied sciences, technology |
| NTC | Nordic Timber Council | In English | → Forestry |
| NTNUI | Norges teknisk-naturvitenskapelige universitets idrettsforening | In Norwegian | → Higher education, universities → Sport, physical exercises |
| NTO | Nederlandse Thuiswinkel Organisatie (www.thuiswinkel.org) | In Dutch | |
| NTSC | National Television Standards Committee | In English | → Telecommunications |
| NTVV | Nieuwe Tongense Voetbal Vereniging | In Dutch | → Football and rugby |
| NUT | National Union of Teachers | In English | → Labour, labour economics → Education |
| NUVO | Nederlandse Unie van Optiekbedrijven | In Dutch | |
| NVC | Netterdense Voetbal Club | In Dutch | → Football and rugby |
| NVC | Naarden De Vesting Combinatie | In Dutch | → Sport, physical exercises |
| NVCA | National Venture Capital Association (www.nvca.org) | In English | → Associations → 33676 |
| NVDO | Nederlandse Video Detaillisten Vereniging | In Dutch | |
| NVEOL | Night Vision and Electro-Optical Laboratory | In English | → Research institutes |
| NVG | Nederlandse Verbond van Groothandel | In Dutch | → Trade |
| NVGD | Nederlandse Vereniging van Grammofoonplaten Detailhandelaren | In Dutch | → Music → Trade |
| NVO | Nevyriausybinė organizacija = NRO, ONGs, NGO, ANG, LSM, GKE, ΜΚΟ, NNO, ННО (look above) |
In Lithuanian | |
| NVPHBV | Nederlandse Vereniging voor Patroonherkenning en Beeldverwerking | In Dutch | → Graphical processing → Image processing |
| NVS | Nieuw Vossemeerse Sportvereniging | In Dutch | → Sport, physical exercises |
| NVTG | Nederlandse Vereniging voor Tropische Geneeskunde | In Dutch | → Medicine |
| NVvV | Nederlandse Vereniging voor Vlaggenkunde | In Dutch | → 9299 |
| NVVW | Nederlands Verbond van Detailhandelaren in Verf en Wandbekleding | In Dutch | → Trade |
| NWC | NOAD Wilhelmina Combinatie | In Dutch | → Sport, physical exercises |
| NWCI | National Women's Council of Ireland | In English | → Feminism |
| NWDV | Nordrhein-Westfälischer Dartverband | In German | → Sport, physical exercises |
| NWP | Netherlands Water Partnership | In English | → Hydrology → Environmental technology, water supply, waste management |
| NWR | Nationale Winkelraad van MKB-Nederland | In Dutch | |
| NWVV | Nieuw Weerdinger Voetbal Vereniging | In Dutch | → Football and rugby |
| NYSAFLT | New York State Association of Foreign Language Teachers (www.nysaflt.org) | In English | → Associations → Education → Language, linguistics, literature |
| NZFA | New Zealand Flag Association | In English | → Associations → 9299 |
| OAB | Oost Arnhemse Boys | In Dutch | → Sport, physical exercises |
| ÖÄGM | Österreichische Ärztegesellschaft für Manuelle Medizin | In German | → Medicine |
| OAH | Organization of American Historians | In English | → History |
| OAIS | Ohio Association of Independent Schools (www.oais.org) | In English | → Associations → Education |
| ÖAMTC | Österreichischer Automobil-, Motorrad- und Touring Club | In German | → Vehicle engineering → Transport and postal services |
| OAPEC | Organization of Arab Petroleum Exporting Countries | In English | → Trade → 665 |
| ÖAR | Österreichische Arbeitsgemeinschaft für Rehabilitation | In German | → Associations |
| OAR | Ordinul Arhitectilor din România | In Romanian | → Architecture |
| OAR | Organization for Asian Research | In English | → Research policy |
| OASIS | Organisation for the Advancement of Structural Information Standard | In English | → Standardization → Data → Networks, communication |
| OAVT | Ontario Association of Veterinary Technicians (www.oavt.org) | In English | → Associations → Veterinary medicine |
| ÖAW | Österreichische Akademie der Wissenschaften | In German | → Academies → Mathematics and natural sciences |
| OB | Onderling Bevriend | In Dutch | → Sport, physical exercises |
| OBDV | Oberbayerischer Dartverband | In German | → Sport, physical exercises |
| OBFA | Occupational Benevolent Funds Alliance | In English | → Labour, labour economics |
| ÖBR | Österreichische Buddhistische Religionsgesellschaft (www.buddhismus-austria.at) | In German | → Buddhism |
| OBV | Order Bossche Voetbalclub | In Dutch | → Football and rugby |
| OBVP | Österreichischer Bundesverband für Psychotherapie (www.psychotherapie.at) | In German | → Psychology → Neurology |
| OBW | Ooij's Blauw Wit | In Dutch | → Sport, physical exercises |
| OCA | Open Content Alliance | In English | → Computer science |
| OCAP | Ontario Coalition Against Poverty | In English | → Economics → Social welfare |
| ÖCG | Österreichische Computer Gesellschaft (www.ocg.at) | In German | → Computer science |
| OCIM | Office de Coopération et d'Information Muséographiques | In French | → Museums |
| OCM | Organisation Civile et Militaire | In French | → History |
| OCM | Organisations Communes des Marchés | In French | → Economics |
| OCOGs | Organising Committees for the Olympic Games | In English | → Sport, physical exercises |
| OCQ | Ordre des Chiropraticiens du Québec | In French | → Occult sciences |
| OCQ | Ordre des Chimistes du Québec | In French | → Chemistry → Chemical technology |
| OCS | Olympic Club de Safi (www.ocs.ma) | In French | → Football and rugby |
| ODB | Ons Doel Bereikt | In Dutch | → Sport, physical exercises |
| ODC | Overwinning Door Combinatie | In Dutch | → Sport, physical exercises |
| ODE | Overwinnen Door Eendracht | In Dutch | → Sport, physical exercises |
| ÖDG | Österreichische Diabetes-Gesellschaft | In German | → Pathology |
| ODI | Ontspanning Door Inspanning | In Dutch | → Sport, physical exercises |
| ODIN | Ons Doel Is Nuttig | In Dutch | → Sport, physical exercises |
| ODIO | Ons Doel Is Overwinnen | In Dutch | → Sport, physical exercises |
| ODIZ | Ons Doel Is Zegevieren | In Dutch | → Sport, physical exercises |
| ODO | Overwinnen Door Oefening | In Dutch | → Sport, physical exercises |
| ODO | Oefening Doet Overwinnen | In Dutch | → Sport, physical exercises |
| ODS | Oefening Doet Slagen | In Dutch | → Sport, physical exercises |
| ODUPA | Organización de Deporte Universitario Panamericano | In Spanish | → Higher education, universities → Sport, physical exercises |
| ODV | Ontspanning Door Voetbal | In Dutch | → Football and rugby |
| OeAV | Österreichischer Alpenverein (www.alpenverein.at) | In German | |
| OECI | Organisation of European Cancer Institutes | In English | → Oncology |
| OECI | Organization of European Cancer Institutes (www.oeci-eeig.org) | In English | → Research institutes → Oncology |
| OEGGG | Österreichische Gesellschaft für Gynäkologie und Geburtshilfe (www.oeggg.at) | In German | → Gynaecology → Obstetrics |
| OEKE | Organizaĵo por Ekonomiaj Kunlaboro kaj Evoluigo | In Esperanto | → Economics |
| OEP | Observatoire Européen du Plurilinguisme | In French | → Language, linguistics, literature |
| OFA | Orthopedic Foundation for Animals (www.offa.org) | In English | → Foundations → Veterinary medicine |
| ÖFAI | Österreichisches Forschungsinstitut für Artificial Intelligence (www.ofai.at) | In German | → Research institutes → Artificial intelligence |
| OFAJ | Office Franco-Allemand pour la Jeunesse | In French | → International relations |
| OFB | Oost Flakkese Boys | In Dutch | → Sport, physical exercises |
| OFC | Oostzaanse Football Club | In Dutch | → Football and rugby |
| OFM | Ordo Fratrum Minorum | In Latin | → Christianity |
| ÖFSE | Österreichische Forschungsstiftung für Entwicklungshilfe | In German | → Foundations → Development |
| ÖFV | Österreichisch-Französische Vereinigung (www.oefv.org) | In German | → International relations |
| ÖGAA | Österreichische Gesellschaft für Astronomie und Astrophysik (www.oegaa.at) | In German | → Astronomy |
| ÖGAA | Österreichische Gesellschaft für Astronomie und Astrophysik (www.oegaa.at) | In German | → Astronomy |
| ÖGAI | Österreichische Gesellschaft für Allergologie und Immunologie | In German | → Immunology and allergy |
| ÖGAM | Österreichische Gesellschaft für Allgemeinmedizin | In German | → Medicine |
| ÖGARI | Österreichische Gesellschaft für Anaesthesiologie, Reanimation und Intensivmedizin | In German | → Traumatology → Anesthesiology |
| ÖGB | Österreichische Gewerkschaftsbund | In German | → Labour, labour economics |
| ÖGB | Österreichischer Gewerkschaftsbund | In German | → Labour, labour economics |
| OGBL | Onofhängege Gewerkschaftsbond Lëtzebuerg | In Letzeburgesh | → Labour, labour economics |
| OGC | Open Geospatial Consortium | In English | → Computer science → Geodesy, cartography |
| ÖGDV | Österreichische Gesellschaft für Dermatologie und Venerologie | In German | → Dermatology |
| OGE | Ordre des Géomètres Experts | In French | → Geodesy, cartography |
| ÖGGG | Österreichische Gesellschaft für Geriatrie und Gerontologie | In German | → Gerontology |
| ÖGGH | Österreichische Gesellschaft für Gastroenterologie und Hepatologie | In German | → Pathology |
| ÖGHO | Österreichische Gesellschaft für Hämatologie und Onkologie | In German | → Oncology |
| ÖGI | Österreichisches Gießerei-Institut | In German | → Research institutes → Metallurgy |
| ÖGI | Österreichisches Getränke-Institut | In German | → Research institutes → Beverage industry |
| ÖGIM | Österreichische Gesellschaft für Innere Medizin | In German | → Medicine |
| ÖGK | Österreichisches Grünes Kreuz (www.gruenes-kreuz.org) | In German | → Medicine |
| OGKA | Österreichische Gesellschaft für kontrollierte Akupunktur | In German | → Medicine |
| ÖGKC | Österreichische Gesellschaft für klinische Chemie | In German | → Biochemistry, biophysics → Pharmacology, toxicology |
| ÖGKJ | Österreichische Gesellschaft für Kinder- und Jugendheilkunde (www.docs4you.at) | In German | → Pediatry |
| ÖGLUT | Österreichische Gesellschaft für Lungenerkrankungen und Tuberkulose | In German | → Chest diseases → Infectious diseases |
| ÖGN | Österreichische Gesellschaft für Neurologie | In German | → Neurology |
| ÖGN | Österreichische Gesellschaft für Nuklearmedizin | In German | → Medicine |
| ÖGP | Österreichische Gesellschaft für Pneumologie | In German | → Chest diseases |
| ÖGPB | Österreichische Gesellschaft für Neuropsychopharmakologie und Biologische Psychiatrie | In German | → Pharmacology, toxicology → Neurology → Psychiatry |
| ÖGPH | Österreichische Gesellschaft für Public Health | In German | → Medicine |
| ÖGPMR | Österreichische Gesellschaft für Physikalische Medizin und Rehabilitation | In German | → Medicine |
| ÖGRME | Österreichische Gesellschaft für Reproduktionsmedizin und Endokrinologie | In German | → Gynaecology |
| ÖGS | Österreichische Gesellschaft für Senologie | In German | → Medicine |
| ÖGSMSF | Österreichische Gesellschaft für Schlafmedizin und Schlafforschung | In German | → Medicine |
| ÖGT | Österreichische Gesellschaft der Tierärzte (www.vu-wien.ac.at/oegt/) | In German | → Veterinary medicine |
| ÖGUM | Österreichische Gesellschaft für Ultraschall in der Medizin | In German | → Medicine |
| OHA | Oral History Association | In English | → Associations → History |
| OHT | Organization of History Teachers | In English | → Education → History |
| OHVV | Ouden Hoornse Voetbal Vereniging | In Dutch | → Sport, physical exercises |
| OIAC | Organisation pour l'Interdiction des Armes Chimiques (www.opcw.org) = OPWC | Organisation for the Prohibition of Chemical Weapons | In English |
In French | → International relations → Military engineering |
| ÖIAT | Österreichisches Institut für angewandte Telekommunikation | In German | → Research institutes → Telecommunications |
| OIBT | Organisation Internationale des Bois Tropicaux (www.itto.or.jp) = ITTO | International Tropical Timber Organization | In English = OIMT | Organización Internacional de las Maderas Tropicales | In Spanish |
In French | → Nature and society → Timber and woodworking industry |
| OIC | Organization of the Islamic Conference | In English | → Islam → International relations |
| OIC | Organisation of the Islamic Conference | In English | → Islam |
| OIE | Office International des Épizooties (www.oie.int) | In French | → Veterinary medicine |
| OIEau | Office International de l'Eau | In French | → Hydrology → Environmental technology, water supply, waste management |
| OIETAI | Organization for Investment, Economic and Technical Assistance of Iran | In English | → Economics → 33972 |
| OIF | Osteogenesis Imperfecta Foundation | In English | → Foundations → Pathology |
| OIML | Organisation Internationale de Métrologie Légale | In French | → Standardization |
| OIMT | Organización Internacional de las Maderas Tropicales (www.itto.or.jp) = OIBT, ITTO (look above) |
In Spanish | → Nature and society → Timber and woodworking industry |
| OING | Organización Internacional No Gubernamental | In Spanish | |
| OIV | Organisation Internationale de la Vigne et du Vin | In French | → Agricultural sciences → Beverage industry |
| OJC | ODI Juliana Combinatie | In Dutch | → Sport, physical exercises |
| OJC | Organisation Juive de Combat | In French | → Judaism → History |
| ÖKG | Österreichische Kardiologische Gesellschaft | In German | → Cardiology |
| ÖKISTA | Österreichisches Komitee für Internationalen Studentenaustausch | In German | → International relations → Higher education, universities |
| OKSV | Overlangel en Keentse Voetbal Club | In Dutch | → Football and rugby |
| OKVC | Oldehoven Kommerzijlse Voetbal Club | In Dutch | → Football and rugby |
| OLIVEO | Onze Leus Is Vooruit En Overwinnen | In Dutch | → Sport, physical exercises |
| OLIVIO | Onze Leus Is Voorwaarts In Overwinning | In Dutch | → Sport, physical exercises |
| OMC | OSS Merwesteijn Combinatie | In Dutch | → Sport, physical exercises |
| OMG | Object Management Group | In English | → Software |
| OML | Oddział Metali Lekkich | In Polish | → Research institutes → Metallurgy |
| OMNSH | Observatoire des Mondes Numériques en Sciences Humaines (www.omnsh.org) | In French | → Computer science → Social sciences |
| OMSP | Organización Mundial de la Salud Pública | In Spanish | → International relations → Public health and hygiene |
| ONA | Ontspanning Na Arbeid | In Dutch | → Sport, physical exercises |
| ONB | Op Nije Begon'n | In Dutch | → Sport, physical exercises |
| ONDO | Op Naar De Overwinning | In Dutch | → Sport, physical exercises |
| ONE | Organisation Naturiste Européenne (www.onenaturism.com) | In English | |
| ONEP | Office National de l'Eau Potable | In French | → Environmental technology, water supply, waste management |
| ONG | Organizzazione non governativa = NRO, ONGs, NGO, ANG, LSM, GKE, ΜΚΟ, NNO, ННО, NVO (look above) |
In Italian | |
| ONG | Organización non gobernamental = NRO, ONGs, NGO, ANG, LSM, GKE, ΜΚΟ, NNO, ННО, NVO (look above) |
In Galician |
|