Organizations promoting the dissemination of Esperanto as an international auxiliary language have historically played a prominent role in assisting individuals affected by war and conflict. During the First World War, the Universal Esperanto Association helped members of the general public stranded in foreign countries, with volunteers delivering private correspondence, tracing missing persons, sending food and medicine, repatriating children, and assisting prisoners of war.^[1] During the Second World War, international Esperanto organizations performed a similar function, delivering correspondence, assisting refugees, and reuniting families.^[1]

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The following is a list of Esperanto organizations affiliated with the Universal Esperanto Association or the World Anational Association, as well as other independent Esperanto-related groups.

• Universal Esperanto Association (Universala Esperanto-Asocio, UEA)

• World Anational Association (Sennacieca Asocio Tutmonda or SAT)

• Agriculture: International Agricultural Esperanto Association (Internacia Agrikultura Esperanto-Asocio, IAEA)
• Art: Universal Artistic League of Esperantists (Universala Artista Ligo de Esperantistoj, UALE)
• Atheism: World Atheist Esperanto Organisation (Ateista Tutmonda Esperanto-Organizo, ATEO)
• Cats: Cat Circle (Rondo Kato)

Esperantist Cat Lovers (Esperantista Kat-amikaro)

• Chess: International Esperanto Chess League (Esperanta Ŝak-Ligo Internacia, EŜLI)
• Construction: World Association of Construction Esperantists (Tutmonda Asocio de Konstruistoj Esperantistaj, TAKE)
• Cycling: International Movement of Esperanto Bicyclists (Biciklista Esperanto Movado Internacia, BEMI).
• Disabilities: Association of Handicapped Esperantists (Asocio de Esperantistaj Handikapuloj, AEH)
• Economics: International Commerce and Economics Professional Group (Internacia Komerca kaj Ekonomia Fakgrupo, IKEF)
• Education: International League of Esperanto Instructors (Internacia Ligo de Esperantistaj Instruistoj, ILEI)
• Ethnic groups: International Committee for Ethnic Liberties (Internacia Komitato por Etnaj Liberecoj, IKEL)
• Europe: European Esperanto Union (Eŭropa Esperanto-Unio, EEU)

European Club (Eŭropa Klubo)

Association for a European Identity (Asocio por Eŭropa Konscio AEK)

• Go (game): International Esperanto Go League (Esperantista Go-Ligo Internacia, EGLI)
• Homosexuality: International Association of Gay and Lesbian Esperantists (Ligo de Samseksamaj Geesperantistoj, LSG)
• Journalism: World Esperantist Journalist Association (Tutmonda Esperantista Ĵurnalista Asocio TEĴA)
• Literature: Association of Esperanto Writers (Esperantlingva Verkista Asocio, EVA)

Centre PEN Esperanto (Esperanta PEN-Centro)

• Law: Esperanto Law Association (Esperanta Jura Asocio)
• Music: Esperanto Music League (Muzika Esperanto Ligo, MEL)

EUROKKA (EUROKKA ou Esperanto-Rok-Asocio)

Klavar Association of the Netherlands (Klavar-unuiĝo Nederlanda, KuN)

• Naturism: International Esperanto Naturist Organisation (Internacia Naturista Organizo Esperantista, INOE)
• Non-smokers: World Association of Esperantist Non-smokers (Tutmonda Asocio de Esperantistaj Nefumantoj, TAdEN)
• Pedagogy: International Group for a Modern Education with Esperanto (Internacia Celado por Edukado Moderna per Esperanto, ICEM Esperanto)
• Philately: Philatelist Esperanto League (Esperanto-Ligo Filatelista, ELF)

Friendly Circle of Esperanto-items Collectors (Amika Rondo de Esperantaĵ-Kolektantoj, AREK)

• Philosophy: World Philosophy Association (Filozofia Asocio Tutmonda, FAT)
• Post and telecommunications: International Esperanto Association of Post and Telecommunication (Internacia Poŝtista kaj Telekomunikista Esperanto-Asocio, IPTEA)
• Radio: Esperanto Friendship on the Radio (Amikaro de Esperanto en Radio, AERA)

International League of Esperantist Radio Amateurs (Internacia Ligo de Esperantistaj Radioamatoroj, ILERA)

• Railroads: International Railroad Esperanto Federation (Internacia Fervojista Esperanto-Federacio, IFEF)
• Rotary International: Friendship of Rotarian Esperantists (Rotaria Amikaro de Esperantistoj, RADE)
• Scouting: League of Esperanto Scouts (Skolta Esperanto Ligo, SEL)
• Solidarity: World Solidarity Against Hunger (Monda Fonduso de Solidareco Kontraŭ la Malsato)

Internet solidarity (Solidareca Reto)

• Syndicalism: Syndical Action (Sindikata Agado)
• Tourism: World Tourism (Monda Turismo, MT)
• Translation: (Internacia Traduk-Reto pere de Esperanto, ITRE)
• Universalism: Universal Alliance (Alianco Universala)
• Vegetarianism: World Vegetarian Esperanto Association (Tutmonda Esperantista Vegetarana Asocio, TEVA)
• Visual impairment: International League of Blind Esperantists (Ligo Internacia de Blindaj Esperantistoj, LIBE)
• Youth: World Esperanto Youth Organization (Tutmonda Esperantista Junulara Organizo, TEJO)
• Institute Martinus (Martinus-lnstituto)
• International Esperanto Centre of Citizens of the World (Esperantista Internacia Centro de la Civitanoj de la Mondo)
• Circle of Friends of Bruno Gröning (Amikaro Bruno Gröning)
• Esperanto Veterans Club (Veterana Esperantista Klubo, VEK)
• Movement Without a Name (Movado sen Nomo, MsN)
• Spirit of Hope (Espermenso)
• Chain of Esperanto Motorcyclists (Esperantista Motorciklanta Ĉeno, EMĈ)
• (Internacia Forstista Rondo Esperantlingva, IFRE)
• (Hejmoj de Internacia Kulturo, HIK)
• (Organiza Societo de Internaciaj Esperanto-Konferencoj, OSIEK)
• (Esperanto-Fako de la Naturamika Internacio, TANEF)
• (CEUFO - regiona Esperanta centro pri nifologio)
• (Asocio de Sociallaboristoj Esperantistaj, ASLE)

• Academy of Esperanto (Akademio de Esperanto)
• International Academy of Sciences (Akademio Internacia de la Sciencoj AIS)
• French Esperanto Institute (Franca Esperanto-Instituto FEI)
• Italian Esperanto Institute (Istituto Italiano di Esperanto IIE)
• Pakistan Esperanto Institute (Pakistana Esperanto-Instituto PEI)