| ORPCF | Organisation pour la Reconstruction du Parti Communiste de France | In French | |
| OSMOI | Organisation Spéciale de la Main d’Oeuvre Immigrée | In French | → History |
| OWP | Organizacja Wyzwolenia Palestyny = PLO | Palestine Liberation Organization | In English = FAT | Fələstin Azadlıq Təşkilatı | In Azerbaijani = ООП | Организация за освобождение на Палестина | In Bulgarian = OAP | Organització per a l'Alliberament de Palestina | In Catalan = OOP | Organizace pro osvobození Palestiny | In Czech = OLP | Organización para la Liberación de Palestina | In Spanish = OLP | Organisation de Libération de la Palestine | In French = PAE | Palestinaren Askapenerako Erakundea | In Basque = OLP | Organizaĵo por Liberigo de Palestino | In Esperanto = OLP | Organización para a Liberación da Palestina | In Galician = PLO | 팔레스타인 해방기구 | In Korean = OLP | Organização para a Libertação da Palestina | In Portuguese = PLO | パレスチナ解放機構 | In Japanese = ПЛО | Палестинската ослободителна организација | In Macedonian = PIO | Palestinos išsivadavimo organizacija | In Lithuanian = პგო | პალესტინის განთავისუფლების ორგანიზაცია | In Georgian = OLP | Organizzazione per la Liberazione della Palestina | In Italian = ООП | Организация освобождения Палестины | In Russian = ПЛО | Палестинска ослободилачка организација | In Serbian = PLO | 巴勒斯坦解放組織 | In Chinese = OВП | Організація визволення Палестини | In Ukrainian = FKÖ | Filistin Kurtuluş Örgütü | In Turkish |
In Polish | |
| OВП | Організація визволення Палестини = OWP, PLO, FAT, ООП, OAP, OOP, OLP, PAE, ПЛО, PIO, პგო, FKÖ (look above) |
In Ukrainian | |
| PAE | Palestinaren Askapenerako Erakundea = OWP, PLO, FAT, ООП, OAP, OOP, OLP, ПЛО, PIO, პგო, OВП, FKÖ (look above) |
In Basque | |
| PARTEI | Partei für Arbeit, Rechtsstaat, Tierschutz, Elitenförderung & basisdemokratische Initiative | In German | |
| PAS | Parti Islam SeMalaysia | In Malay | → Islam |
| PCC | Parti Communiste Chinois | In French | |
| PCF | Parti Communiste Français | In French | |
| PCMLF | Parti Communiste Marxiste-Léniniste de France | In French | |
| PCO | Partido Comunista de España | In Spanish | |
| PCOF | Parti Communiste des Ouvriers de France | In French | |
| PCP | Partido Comunista Português | In Portuguese | |
| PCUS | Partito Comunista dell'Unione Sovietica = PCUS | Parti Communiste de l'Union Soviétique | In French = SKUS | Strollad Komunour an Unaniezh Soviedel | In Breton = KPdSU | Kommunistische Partei der Sowjetunion | In German = KПCC | Коммунистическая партия Советского Союза | In Russian = KПCC | Kommunistitscheskaja Partija Sowjetskogo Sojusa | In Russian = KSSR | Komunistická strana Sovětského svazu | In Czech = KPSU | Komunisma Partio de Soveta Unio | In Esperanto = KPSU | Komunisma Partio de Soveta Unio | In Esperanto |
In Italian | |
| PCUS | Parti Communiste de l'Union Soviétique = SKUS, KPdSU, KПCC, KSSR, KPSU (look above) |
In French | |
| PDE | Partit Demòcrata Europeu | In Catalan | |
| PDS | Parti Démocratique Sénégalais | In French | |
| PES | Party of European Socialists = PES | Partia Europejskich Socjalistów | In Polish = PSE | Parti Socialiste Européen | In French = ESP | Europeiska socialdemokratiska partiet | In Swedish = PSE | Partito del Socialismo Europeo | In Italian |
In English | |
| PES | Partia Europejskich Socjalistów = PSE, ESP (look above) |
In Polish | |
| PEV | Parti Évangélique (www.evppev.ch) = EVP | Evangelische Volkspartei | In German |
In French | → Christianity |
| PGS | Primorsko Goranski Savez (www.pgs.hr) | In Croatian | |
| PGS | Primorsko-Goranski Savez (www.pgs.hr) | In Croatian | |
| PGSU | Primorsko Goranska Stranka Umirovljenika | In Croatian | |
| PIO | Palestinos išsivadavimo organizacija = OWP, PLO, FAT, ООП, OAP, OOP, OLP, PAE, ПЛО, პგო, OВП, FKÖ (look above) |
In Lithuanian | |
| PKM | Partit Komunista Malti | In Maltese | |
| PL | Partit Laburista = MLP | Malta Labour Party | In English |
In Maltese | |
| PLO | パレスチナ解放機構 = OWP, FAT, ООП, OAP, OOP, OLP, PAE, ПЛО, PIO, პგო, OВП, FKÖ (look above) |
In Japanese | |
| PLO | 팔레스타인 해방기구 = OWP, FAT, ООП, OAP, OOP, OLP, PAE, ПЛО, PIO, პგო, OВП, FKÖ (look above) |
In Korean | |
| PLO | 巴勒斯坦解放組織 = OWP, FAT, ООП, OAP, OOP, OLP, PAE, ПЛО, PIO, პგო, OВП, FKÖ (look above) |
In Chinese | |
| PLO | Palestine Liberation Organization = OWP, FAT, ООП, OAP, OOP, OLP, PAE, ПЛО, PIO, პგო, OВП, FKÖ (look above) |
In English | |
| PLQ | Parti Libéral du Québec | In French | |
| PMN | Parti Mahasiswa Negara | In Malay | |
| PN | Partit Nazzjonalista | In Maltese | |
| PNB | Parti Nationaliste Basque (www.eaj-pnb.eu) | In French | |
| PNC | Parti de la Nation Corse | In French | |
| PNC | Partitu di a Nazione Corsu | In Corsican | |
| PNO | Partit de la Nacion Occitana | In Occitan | |
| PNO | Parti Nationaliste Occitan | In French | |
| PNR | Partido Nacional Renovador | In Portuguese | |
| PNV | Partido Nacionalista Vasco (www.eaj-pnv.eu) = EAJ | Euzko Alderdi Jeltzalea | In Basque |
In Spanish | |
| POc | Partit Occitan | In Occitan | |
| POSL | Parti Ouvrier Socialiste Luxembourgeois = LSAP | Lëtzebuerger Sozialistesch Aarbechterpartei | In Letzeburgesh = LSAP | Luxemburger Sozialistische Arbeiterpartei | In German = LSAP | Luxemburgse Socialistische Arbeiderspartij | In Dutch |
In French | |
| POWN | Polska Organizacja Walki o Niepodleglość | In Polish | → History |
| PPE | Partit Popular Europeu | In Catalan | |
| PPF | Parti Populaire Français | In French | → History |
| PPS | Partija Podunavskih Srba | In Croatian | |
| PQ | Parti Québécois | In French | |
| PRCF | Pôle de Renaissance Communiste en France | In French | |
| PRG | Parti Radical de Gauche | In French | |
| PS | Podravska Stranka | In Croatian | |
| PS | Partido Socialista | In Portuguese | |
| PS | Parti Socialiste | In French | |
| PSA | Pàrtaidh Shòisealach na h-Alba = SSP | Scottish Socialist Party | In English |
In Scottish Gaelic | |
| PSD | Partidul Social Democrat (www.psd.ro) | In Romanian | |
| PSD | Partido Social Democrata | In Portuguese | |
| PSD | Partidul Social Democrat din Moldova (www.psdm.md) | In Moldavan | |
| PSDLO | Páirtí Sóisialta Daonlathach an Lucht Oibre = SDLP | Social Democratic and Labour Party | In English |
In Irish | |
| PSDMR | Partidul Social Democrat al Muncii din Rusia = РСДРП | Росси́йская Социа́л-Демократи́ческая Рабо́чая Па́ртия | In Russian |
In Romanian | |
| PSE | Partito del Socialismo Europeo = PES, ESP (look above) |
In Italian | |
| PSE | Parti Socialiste Européen = PES, ESP (look above) |
In French | |
| PSF | Parti Social Français | In French | |
| PSI | Partitu Sucialistu per l'Indipendenza | In Corsican | |
| PSOE | Partido Socialista Obrero Español | In Spanish | |
| PSS | Posavsko Slavonska Stranka | In Croatian | |
| PT | Parti des Travailleurs | In French | |
| PUR | Parti de l'Union Radicale | In French | |
| PvdA | Partij van de Arbeid | In Dutch | |
| PZPR | Polska Zjednoczona Partia Robotnicza | In Polish | |
| RAF | Rote Armee Fraktion | In German | |
| RAI | Mouvement des Jeunes Socialistes | In French | |
| RCF | Rassemblement des Contribuables Français | In French | |
| RD | Rassemblement Démocrate | In French | |
| RDA | Rassemblement Démocratique Africain | In French | |
| ReSo | Réformistes et Solidaires | In French | |
| RGR | Rassemblement des Gauches Républicaines | In French | |
| RIF | Rassemblement pour l'Indépendance et la souveraineté de la France | In French | |
| RKP | Ruotsalainen Kansanpuolue = SFP | Svenska folkpartiet | In Swedish |
In Finnish | |
| RN | Renovación Nacional | In Spanish | |
| RNC | Republican National Committee | In English | |
| RNP | Rassemblement National Populaire | In French | |
| RPF | Rassemblement Pour la France | In French | |
| RPF | Rassemblement du Peuple Français | In French | |
| RPFC | Rassemblement du Peuple Franc-Comtois | In French | |
| RPR | Rassemblement pour la République | In French | |
| RPS | Rapski Pučki Sabor (www.rps.hr) | In Croatian | |
| RSS | Rashtriya Swayamsevak Sangh = RSS | राष्ट्रीय स्वयंसेवक संघ | In Hindi |
In English | |
| RSS | राष्ट्रीय स्वयंसेवक संघ = (look above) |
In Hindi | |
| S-BHS | Slavonsko-Baranjska Hrvatska Stranka | In Croatian | |
| SAP | Socialdemokratiska arbetarepartiet | In Swedish | |
| SBHS | Slavonsko-Baranjska Hrvatska Stranka | In Croatian | |
| SDBS | Srpska Demokratska Baranjska Stranka | In Croatian | |
| SDI | Socialisti Democratici Italiani (www.sdionline.it) | In Italian | |
| SDLP | Social Democratic and Labour Party = PSDLO (look above) |
In English | |
| SDP | Suomen Sosialidemokraattinen Puolue | In Finnish | |
| SDP | Socijaldemokratska Partija (www.sdp.hr) | In Croatian | |
| SDP | Socijaldemokratska Partija Hrvatske (www.sdp.hr) | In Croatian | |
| SDP | Socijaldemokratska partija (Hrvatske) | In Croatian | |
| SDSS | Samostalna Demokratska Srpska Stranka (www.sdss.hr) | In Croatian | |
| SDU | Socijalno-Demokratska Unija Hrvatske | In Croatian | |
| SEA-PZS | Srednjoeuropska Akcija - Pokret za Srednju Europu | In Croatian | |
| SFIO | Section Française de l'Internationale Ouvrière | In French | |
| SFIO | Section Française de l’Internationale Ouvrière | In French | |
| SFP | Svenska folkpartiet = RKP (look above) |
In Swedish | |
| SHB | Stranka Hrvatskih Branitelja | In Croatian | |
| SHUS | Savez Hrvatskih Umirovljenika i Seniora | In Croatian | |
| SIL | Solidarité Internationale Libertaire = ILS | International Libertarian Solidarity | In English |
In French | → Organizations and associations |
| SKUS | Strollad Komunour an Unaniezh Soviedel = PCUS, KPdSU, KПCC, KSSR, KPSU (look above) |
In Breton | |
| SNL | Sjedinjene Nezavisne Liste (www.snl.hr) | In Croatian | |
| SNM | Service National Maquis | In French | → Military affairs → History |
| SNP | Scottish National Party | In English | |
| SNS | Srpska Narodna Stranka | In Croatian | |
| SP | Solidarité et Progrès | In French | |
| SPA | Socialistische Partij Anders | In Dutch | |
| SPD | Stranka Pravične Demokracije | In Croatian | |
| SPD | Sozialdemokratische Partei Deutschlands | In German | |
| SPH | Socijalistička Partija Hrvatske | In Croatian | |
| SPÖ | Sozialdemokratische Partei Österreichs | In German | |
| SPOT | Stranka Potrošača | In Croatian | |
| SRH | Stranka Roma Hrvatske | In Croatian | |
| SRP | Socijalistička Radnička Partija Hrvatske (www.srp.hr) | In Croatian | |
| SRP | Socijalistička radnička partija (Hrvatske) | In Croatian | |
| SRPJ | Socijalistička radnička partija Jugoslavije | In Croatian | |
| SSH | Slobodarska Stranka Hrvatske | In Croatian | |
| SSP | Scottish Socialist Party = PSA (look above) |
In English | |
| SU | Stranka Umirovljenika | In Croatian | |
| TDS | Turopoljska Demokratska Stranka | In Croatian | |
| U2R | Union des Républicains Radicaux | In French | |
| UA | Union des Anarchistes | In French | |
| UC | Unitat Catalana | In Catalan | |
| UCE | Union des Candidats Émergents | In French | |
| UDF | Union pour la Démocratie Française | In French | |
| UDR | Union pour la Défense de la République | In French | |
| UDR | Union des Démocrates pour la République | In French | |
| UDSR | Union Démocratique et Socialiste de la Résistance | In French | → History |
| UDT | Union Démocratique du Travail | In French | |
| UEF | Unio de la Europaj Federistoj = UEF | Union of European Federalists | In English |
In Esperanto | |
| UEF | Union of European Federalists = (look above) |
In English | |
| UEM | Union En Mouvement | In French | |
| UEP | Union des Étudiants pour le Progrès | In French | |
| UFF | Union des Femmes Françaises | In French | → History |
| UFP | Union des Forces de Progrès | In French | |
| UFP | Union des Forces Progressistes | In French | |
| UGFR | Union Gaulliste pour une France Républicaine | In French | |
| UGIF | Union Générale des Israélites de France | In French | → Organizations and associations |
| UJP | Union des Jeunes pour le Progrès | In French | |
| UJRF | Union de la Jeunesse Républicaine de France | In French | |
| UMP | Union pour un Mouvement Populaire | In French | |
| UMP | Union pour la Majorité Présidentielle | In French | |
| UNE | Union Nationale Espagnole | In French | |
| UNR | Union pour la Nouvelle République | In French | |
| UPA | Union du Peuple Alsacien | In French | |
| UPC | Union des Populations du Cameroun | In French | |
| UPC | Union du Peuple Corse | In French | |
| UPF | Union Pour la France | In French | |
| UPF | Union du Peuple Français | In French | |
| UPLD | Union pour la Démocratie | In French | |
| URC | Union de la République et du Centre | In French | |
| URCF | Union des Révolutionnaires-Communistes de France | In French | |
| URD | Union Républicaine Démocratique | In French | |
| USD | Union Sociale Démocratique | In French | |
| VAR | Vrij-Antirevolutioniare Partij | In Dutch | |
| WCV | Washington Conservation Voters (www.wcvoters.org) | In English | |
| ZD | Zeleni Demokrati | In Croatian | |
| ZDS | Zagorska Demokratska Stranka (www.zds.hr) | In Croatian | |
| ZS | Zagorska Stranka | In Croatian | |
| ZSMP | Związek Socjalistycznej Młodzieży Polskiej | In Polish | |
| ĐCSVN | Đảng Cộng sản Việt Nam | In Vietnamese | |
| ΑΚΕΛ | Ανορθωτικό Κόμμα Εργαζόμενου Λαού | In Greek | |
| ΕΔΕ | Ευρώπη - Δημοκρατία - Εσπεράντο (www.e-d-e.org) = EDE | Europe Démocratie Espéranto | In French = EDE | Eŭropo Demokratio Esperanto | In Esperanto = EDE | Europa Demokratie Esperanto | In German = EDE | Europe Democracy Esperanto | In English = EDE | Europa Democrazia Esperanto | In Italian = EDE | Europa Democracia Esperanto | In Spanish = EDE | Europa Demokracija Esperanto | In Croatian = EDE | Europa Democratie Esperanto | In Dutch = EDE | Európa Demokrácia Eszperantó | In Hungarian = EDE | Europa Demokratija Esperanto | In Lithuanian = EDE | Europa Demokracja Esperanto | In Polish = EDE | Europa Demokrati Esperanto | In Swedish |
In Greek | |
| БСП | Българската социалистическа партия | In Bulgarian | |
| ООП | Организация за освобождение на Палестина = OWP, PLO, FAT, OAP, OOP, OLP, PAE, ПЛО, PIO, პგო, OВП, FKÖ (look above) |
In Bulgarian | |
| ООП | Организация освобождения Палестины = OWP, PLO, FAT, OAP, OOP, OLP, PAE, ПЛО, PIO, პგო, OВП, FKÖ (look above) |
In Russian | |
| ПЛО | Палестинска ослободилачка организација = OWP, PLO, FAT, ООП, OAP, OOP, OLP, PAE, PIO, პგო, OВП, FKÖ (look above) |
In Serbian | |
| ПЛО | Палестинската ослободителна организација = OWP, PLO, FAT, ООП, OAP, OOP, OLP, PAE, PIO, პგო, OВП, FKÖ (look above) |
In Macedonian | |
| РСДРП | Росси́йская Социа́л-Демократи́ческая Рабо́чая Па́ртия = PSDMR (look above) |
In Russian | |
| حماس | حركة المقاومةالاسلامية | In Arabic | |
| პგო | პალესტინის განთავისუფლების ორგანიზაცია = OWP, PLO, FAT, ООП, OAP, OOP, OLP, PAE, ПЛО, PIO, OВП, FKÖ (look above) |
In Georgian |
|