Committee for a Marxist International (CMI)

Committee for a Workers' International (CWI) 

Communist International Marxists-Leninists

Communist Organization for the Fourth International (COFI)

Coordination Committee for the Construction of the International Workers Party (KoorKom), other page, periodical Marxism Alive

Coordinating Committee for the Refoundation of the Fourth International (CRFI)  

Fourth Internationalist Tendency (Tendência Quarta Internacionalista, TQI)  

Internal Fraction of the International Communist Current

International Bolshevik Tendency (IBT)

International Bureau for the Revolutionary Party (IBRP), mirror page

International Center of Orthodox Trotskyism (Centro Internacional del Trotskismo Ortodoxo - IV Internacional, CITO), mirror page, other page

International Committee of the Fourth International (ICFI)

International Communist Current (ICC)

International Communist League (Fourth Internationalist) (ICL(FI))

International Communist Party [Bolletino] (Partito Comunista Internazionale [Bolletino]) unofficial

International Communist Party [Il Comunista] (Partito Comunista Internazionale [Il Comunista]) unofficial

International Communist Party [Il Partito Comunista] (Partito Comunista Internazionale [Il Partito Comunista]), mirror page, unofficial page

International Communist Party [Il Programma Comunista] (Partito Comunista Internazionale [Il Programma Comunista]) unofficial (Partito Comunista Internazionale [Il Programma Comunista]) unofficial (Partito Comunista Internazionale [Il Programma Comunista]) unofficial

International Communist Seminar

International Conference of Marxist-Leninist Parties and Organizations [Hoxhaist] (ICMLPO[H])

International Conference of Marxist-Leninist Parties and Organizations [Maoist] (ICMLPO[M])

International Leninist Current (ILC)

International Secretariat of the Fourth International (Secrétariat International de la Quatrième Internationale), mirror page, periodical La Vérité/The Truth

International Struggle Marxist-Leninist (ISML), mirror page

International Trotskyist Opposition (ITO)

International Workers Association (Asociación International de los Trabajadores, IWA/AIT), unofficial page

International Workers League (Fourth International) (Liga Internacional de los Trabajadores (Quarta Internacional), LIT-CI)

International Workers' Unity (Fourth International) (Unidad Internacional de los Trabajadores (Quarta Internacional), UIT)

Internationalist Communist Group (Groupe Communiste Internationaliste, GCI)

Internationalist Communist Union (Union Communiste Internationaliste, UCI)

Internationalist Perspective

League for a Revolutionary Communist International  (LRCI)

League for the Fifth International (L5I) 

League for the Fourth International (LFI)

Liaison Committee of Militants for a Revolutionary Communist International (LCMRCI), mirror page

n+1 Review

Movement for the Refoundation of the Fourth International (MRFI)

Northeastern Federation of Anarchist Communists (NEFAC)

Organizing Committee of Principist Trotskyism (Fourth International) (Comité Organizador del Trotskismo Principista (Cuarta Internacional), COTP-CI)

Party of the European Left, other page 

Revolutionary Internationalist Movement, periodical A World to Win

Revolutionary Workers Foment (Fomento Obrero Revolucionario, FOR), other page

SWP-Tendency periodical Militant

Trotskyist Faction (Estrategia Internacional) (Fracción Trotskista (Estrategia Internacional), FT(EI))

United Secretariat of the Fourth International (USFI), mirror page 

Vanguard - Marxist-Leninist-Maoist Parties waging or supporting People's War

World Socialist Movement (World Socialist Movement, WSM)

World Peace Council

Workers International to Rebuild the Fourth International (WIRFI)

World Federation of Democratic Youth

International Union of Students

Youth for International Socialism

World Federation of Trade Unions

Industrial Workers of the World (IWW) 

Internationalist Workers' Group (Groupe Internationaliste Ouvrier)

International Workers' League (Liga Internacional de los trabajadores)

Workers Democracy Network 

Workers' International League

Workers on the WWW

Association for Workers' Emancipation (Asociatia pentru Emanciparea Muncitorilor), periodical Tribuna Socialã - Romania 

Independent Working Class Association (IWCA), local group - Great Britain

Italian Syndical Union - International Workers' Association (Unione Sindacale Italiana - Associazione Internazionale dei Lavoratori, USI)

Power of Working Class (Nodongja-euy Him, PWC) - Korea, Republic

Workers' Democracy (Ergatiki Demokratia) - Cyprus

Union of Circles for Workers' Politics (Union des Cercles pour une Politique Ouvrière, UCPO) - Switzerland

Alternative and United Left (Esquerra Unida i Alternativa, EUiA), Spain, left socialist/communist

Black Radical Congress (BRC), USA

Communist Association - Future (Kyôsanshugi Kyôgikai - Mirai, COM-Future / Komu-Mirai), Japan, radical left

Communist Refoundation (Refundación Comunista), Argentina

Democratic Front for Peace and Equality (Hazit Democratit le-Shalom ve-Shivayon/Al-Jabha al-Dimuqratiyya Lil Salam Wal-Musawa, Chadash), Israel, communist dominated

Front of the Radical Left (Metopo Rizospastikis Aristeras), other page, radical left 

Red Electoral Alliance (Rød Valgallianse, RV), Norway, radical left

Socialist Alliance, Australia

Socialist Alliance, Great Britain

The Left (La Izquierda), Chile, dominated by Communist Party

The Left (Déi Lénk / La Gauche / Die Linken), Luxemburg, radical left

Union of Communist Parties - Communist Party of the Soviet Union (Soyuz Kommunisticheskih Partii - Kommunisticheskaya Partiya Sovetskogo Soyuza, SKP-KPSS)

United Left (Izquierda Unida) unofficial, Argentina, communist dominated

United Left (Izquierda Unida, IU) unofficial, Bolivia, communist dominated

United Left (Izquierda Unida, IU), Spain, communist dominated

Unity List - The Red-Greens (Enhedslisten - De Rød-Grønne), Denmark, radical left

Workers Left Unity (Ettehad-e Chap-e Kargari), Iran, radical left

Yugoslav Left (Jugoslovenska Levica, JUL), communist dominated