Socialist International: Political international

Most of its members are democratic socialist, social democratic, and labour political parties.

Socialist International

Countries with members of Socialist International
Abbreviation	SI
Predecessor	Labour and Socialist International
Formation	3 June 1951; 72 years ago (1951-06-03)
Type	International non-governmental organisation
Purpose	"Strengthen relations between the affiliated parties and to coordinate their political attitudes and activities"
Location	London, SW4 United Kingdom
Region served	Worldwide
Membership	147
President	Pedro Sánchez
Secretary General	Luis Ayala [Wikidata]
Main organ	Congress of the Socialist International
Budget	£1.4 million (2014)
Website	socialistinternational.org

Its name is from the Second International, which was formed in 1889 and dissolved on the eve of World War I in 1914.

Some of the Second International's most famous actions were its 1889 declaration of 1 May as International Labour Day and its 1910 declaration of 8 March as International Women's Day. The Second International was split by the outbreak of World War I. A small part carried on as the International Socialist Commission. The International re-formed in 1923 (as the Labour and Socialist International), and was re organised again, in its present form, after World War II. Many social democratic and socialist parties had been suppressed in Nazi-occupied Europe.

Since World War II, the SI helped social democratic parties to re-start themselves when dictatorship gave way to democracy in Portugal (1974) and Spain (1975).

Until its 1976 Geneva Congress, the Socialist International had few members outside Europe and no formal involvement with Latin America. In the 1980s, most SI parties gave their backing to the Nicaraguan Sandinistas (FSLN), whose left-wing government had incited hatred from the United States. Since then, the SI has admitted as member-parties not only the FSLN but also the centre-left Puerto Rican Independence Party, as well as the ex-Communist parties such as the Italian Democrats of the Left (Democratici di Sinistra (DS)) and the Front for the Liberation of Mozambique (FRELIMO).

The Party of European Socialists, a European political party active in the European Parliament, is an associated organisation of the Socialist International.

In 2022, Pedro Sánchez, leader of the Spanish Socialist Workers' Party, became the president of the Socialist International.

• 1951-1957: Morgan Phillips
• 1957-1962: Alsing Andersen
• 1963: Erich Ollenhauer
• 1964-1976: Bruno Pittermann
• 1976-1992: Willy Brandt
• 1992-1999: Pierre Mauroy
• 1999-2005: António Guterres
• 2006-2022: George Papandreou
• 2022-present: Pedro Sánchez

Honorary Presidents

• Ruben Berrios Martinez

Full members

The following parties are full members:

Country	Name	Abbr	Government	Notes
Albania	Socialist Party of Albania	PS	in government	Admitted as consultative member in 1999. Promoted to full member in 2003.
Algeria	Socialist Forces Front	FFS	in opposition	Admitted as consultative member in 1992. Promoted to full member in 1996.
Andorra	Social Democratic Party	PS	in opposition	Promoted to full member in 2003.
Angola	Popular Movement for the Liberation of Angola	MPLA	in government	Admitted as observer member in 1996. Promoted to full member in 2003.
Argentina	Radical Civic Union	UCR	junior party in coalition	Admitted as consultative member in 1996. Promoted to full member in 1999.
Armenia	Armenian Revolutionary Federation	ARF	junior party in coalition	Admitted (as Armenian Socialist Party) as observer member in 1996. Promoted (as ASP) to consultative member in 1999. Promoted (as ASP) to full member in 2003.
Austria	Social Democratic Party of Austria	SPÖ	in opposition	Full member since 1951.
Azerbaijan	Social Democratic Party	ASDP	in opposition	Admitted as observer member in 1996. Promoted to consultative member in 2003. Readmitted as consultative member in June/July 2014. Admitted as full member in 2016.
Belarus	Belarusian Social Democratic Party	BSDP	in opposition	Admitted as observer member in 1999. Promoted to consultative member in 2003. Promoted to full member in November 2015.
Belgium	Socialist Party	PS	in opposition
Bosnia and Herzegovina	Social Democratic Party of Bosnia and Herzegovina	SDP BiH	in opposition	Admitted as observer member in 1996. Promoted to full member in 1999.
Brazil	Democratic Labour Party	PDT	in opposition	Admitted as consultative member in 1986. Promoted to full member in 1989.
Bulgaria	Party of Bulgarian Social Democrats	PBSD	in opposition
Bulgaria	Bulgarian Socialist Party	BSP	in opposition	Admitted as full member in 2003.
Burkina Faso	People's Movement for Progress	MPP	in government	Admitted as full member in 2016.
Cameroon	Social Democratic Front	SDF	in opposition	Admitted as consultative member in 1996. Promoted to full member in 1999.
Cape Verde	African Party for the Independence of Cape Verde	PAICV	in opposition	Admitted as consultative member in 1992. Promoted to full member in 1996.
Central African Republic	Movement for the Liberation of the Central African People	MLPC	in opposition	Admitted as observer member in 2008. Upgraded to full member in 2018.
Chad	National Union for Democracy and Renewal	UNDR	in opposition	Admitted as observer member in June/July 2014. Upgraded to full member in 2017.
Chile	Party for Democracy	PPD	in opposition	Admitted as consultative member in 1992. Promoted to full member in 1996.
Chile	Radical Social Democratic Party	PRSD	in opposition
Chile	Socialist Party of Chile	PS	in opposition	Admitted as consultative member in 1992. Promoted to full member in 1996.
Colombia	Colombian Liberal Party	PLC	in coalition	Admitted as consultative member in 1992. Promoted to full member in 1999.
Costa Rica	National Liberation Party	PLN	in opposition	Full member since 1987.
Croatia	Social Democratic Party of Croatia	SDP	in opposition	Admitted as full member in 1999.
Cyprus	Movement for Social Democracy	EDEK	in opposition	Full member since 1987. Promoted to full member in 1992.
Cyprus (North)	Republican Turkish Party	CTP	in opposition	Admitted as consultative member in 2008 (pending consultation). Promoted to full member in June/July 2014.
Cyprus (North)	Communal Democracy Party	TDP	in opposition	Admitted as consultative member in November 2015. Promoted to full member in March 2017.
Czech Republic	Czech Social Democratic Party	ČSSD	junior party in coalition
Democratic Republic of the Congo	Union for Democracy and Social Progress	UDPS	in opposition	Admitted as observer member in 2003.
Dominican Republic	Dominican Revolutionary Party	PRD	junior party in coalition	Full member since 1987.
Equatorial Guinea	Convergence for Social Democracy	CPDS	in opposition	Admitted as consultative member in 1996. Promoted to full member in 1999.
Finland	Social Democratic Party of Finland	SDP	in government
France	Socialist Party	PS	in opposition
Ghana	National Democratic Congress	NDC	in opposition	Admitted as consultative member in 2003. Promoted to full member in 2008.
Greece	Movement for Change		in opposition	Full member since 1990.
Guatemala	National Unity of Hope	UNE	in opposition	Admitted as full member in 2008.
Guinea	Rally of the Guinean People	RPG	in government	Admitted (as Guinean People's Assembly) as consultative member in 1999. Promoted (as GPA) to full member in 2003.
Haiti	Fusion of Haitian Social Democrats	PFSDH	in opposition	Full member since 1989.
Haiti	Social Democratic Assembly for the Progress of Haiti (RSD)	RSD	in opposition	Admitted as full members in 2018
Hungary	Hungarian Socialist Party	MSzP	in opposition	Admitted as observer member in 1992. Promoted to full member in 1996.
Hungary	Social Democratic Party of Hungary	MSZDP	extra-parliamentary	Member since 1990. Admitted as observer member in 1992. Promoted to consultative member in 1999. Promoted to full member in 2003.
India	Indian National Congress	INC	in opposition	Originally joined in 1993. Readmitted as full member December 2014.
Iran	Kurdistan Democratic Party	KDP	—	Admitted as a full member in November 2015.
Iraq	Patriotic Union of Kurdistan	PUK	in government	Admitted as observer member in 2003. Promoted to full member in 2008.
Ireland	Labour Party		in opposition
Israel	Israeli Labour Party	Avoda	in opposition	Temporarily suspended membership in July 2018 over SI's adoption of BDS policies.
Israel	Meretz		in opposition
Italy	Italian Socialist Party	PSI	in opposition
Jamaica	People's National Party	PNP	in opposition	Full member since 1952. Temporarily demoted to observer member in 2012 due to non-payment of membership fees.
Japan	Social Democratic Party	SDP	in opposition	Full member since 1951 as the Japan Socialist Party.
Kazakhstan	Nationwide Social Democratic Party	OSDP	—	Admitted as consultative member in 2012. Promoted to full member in November 2015.
Kyrgyzstan	Social Democratic Party of Kyrgyzstan	SDPK	in government	Promoted to full member in June 2018.
Lebanon	Progressive Socialist Party	PSP	junior party in coalition	Full member since 1980.
Lithuania	Social Democratic Party of Lithuania	LSDP	junior party in coalition	Full member since the 1990s.
Mali	Alliance for Democracy in Mali	ADEMA-PASJ	in opposition	Admitted as consultative member in 1996. Promoted to full member in 1999. Promoted to full member in 2008.
Mali	Rally for Mali	RPM	in government	Admitted as consultative member in 2003.
Mauritania	Rally of Democratic Forces	RFD	in opposition	Admitted as observer member in 2003. Promoted to full member in 2008.
Mauritius	Labour Party	PT	in opposition	Full member since 1969.
Mauritius	Mauritian Militant Movement	MMM	in opposition	Admitted as consultative member in 1996. Promoted to full member in 2003. Part of the Alliance of the Heart.
Mexico	Institutional Revolutionary Party	PRI	in opposition	Admitted as consultative member in 1996. Promoted to full member in 2003.
Moldova	Democratic Party of Moldova	PDM	junior party in coalition	Admitted as consultative member in 2008. Promoted to full member in 2012. Part of Alliance for European Integration.
Mongolia	Mongolian People's Party	MPP	in government	Admitted (as Mongolian People's Revolutionary Party) as observer member in 1999. Promoted (as Mongolian People's Revolutionary Party) to full member in 2003.
Mongolia	Mongolian Social Democratic Party	MSDP	—	Admitted as consultative member in 1992. Promoted to full member in 1996. Merged with others in 2000 to form the Democratic Party
Montenegro	Democratic Party of Socialists of Montenegro	DPS	senior party in coalition	Admitted as consultative member in 2003. Promoted to full member in 2008.
Montenegro	Social Democratic Party of Montenegro	SDP	in opposition	Admitted as observer member in 1996. Promoted to consultative member in 1999. Promoted to full member in 2003.
Morocco	Socialist Union of Popular Forces	USFP	in opposition	Promoted to full member in 1992.
Mozambique	Frelimo Party	FRELIMO	in government	Admitted as consultative member in 1996. Promoted to full member in 1999.
Namibia	South West Africa People's Organisation	SWAPO	in government	Promoted to full member in 2008.
Nepal	Nepali Congress	NC	in opposition	Admitted as consultative member in 1989. Promoted to full member in 1999.
Niger	Nigerien Party for Democracy and Socialism	PNDS	in government	Admitted as consultative member in 1996. Promoted to full member in 2003.
Pakistan	Pakistan Peoples Party	PPP	in opposition	Admitted as consultative member in 1989. Promoted to full member in 2003.
Palestine	Fatah		in government	Admitted as observer member in 1996. Promoted to consultative member in 1999. Promoted to full member in 2012.
Panama	Democratic Revolutionary Party	PRD	in opposition	Admitted as consultative member in 1986. Admitted as consultative member in 1996. Promoted to full member in 2003.
Paraguay	Democratic Progressive Party	PDP	in opposition	Admitted as consultative member in 2008. Promoted to full member in November 2015.
Peru	American Popular Revolutionary Alliance	APRA	in opposition	Promoted to full member in 1999.
Philippines	Philippines Democratic Socialist Party	PDSP	in opposition	Admitted as consultative member in 1992. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014. Reinstated in 2019.
Portugal	Socialist Party	PS	in government
Puerto Rico	Puerto Rican Independence Party	PIP	in opposition	Consultative member in 1987, full member in 1994. Promoted to full member in 1992.
Romania	Social Democratic Party	PSD	senior party in coalition	Admitted as consultative member in 1996. Promoted to full member in 1999. Consultative member in 1992, full member in 2001. Admitted as full member in 2003.
Russia	A Just Russia	SR	in opposition	Admitted as observer member in 2008. Promoted to consultative member in 2010. Promoted to full member in 2012.
San Marino	Party of Socialists and Democrats	PSD	in opposition	Consultative member in 1961, full member in 1980.
Senegal	Socialist Party of Senegal	PS	—	Full member since the 1970s. Boycotted last election.
Slovakia	Direction – Social Democracy	SMER-SD	senior party in coalition	Full member since 1994.
South Africa	African National Congress	ANC	in government	Admitted as full member in 1999.
Spain	Spanish Socialist Workers' Party	PSOE	in government	Full member since 1951.
Tunisia	Democratic Forum for Labour and Liberties	FDTL	junior party in coalition	Admitted as consultative member in 2003. Demoted to observer member in 2012 due to non-payment of membership fees. Promoted to full member in 2012.
Turkey	Republican People's Party	CHP	in opposition	Took Social Democratic Populist Party's place in 1995.
United Kingdom	Social Democratic and Labour Party	SDLP	in opposition	Full member since 1974.
Uruguay	New Space	PNE	in government	Admitted as consultative member in 1999. Promoted to full member in 2003.
Venezuela	A New Era	UNT	in opposition	Admitted as consultative member in 2013. Promoted to full member in November 2015.
Venezuela	Democratic Action	AD	in opposition	Observer member in 1966, consultative member in 1981, full member mid 1980s.
Venezuela	Popular Will	VP	in opposition	Admitted as full member in December 2014.
Yemen	Yemeni Socialist Party	YSP	in opposition	Admitted as observer member in 2003. Promoted to consultative member in 2008. Promoted to full member in 2012.

Consultative parties

The following parties are consultative parties:

Country	Name	Abbr	Government	Notes
Belize	People's United Party	PUP	in opposition	Admitted as consultative member in June/July 2014.
Botswana	Botswana Democratic Party	BDP	in government	Admitted as consultative member in June/July 2014.
Democratic Republic of the Congo	Unified Lumumbist Party	PALU	in opposition	Admitted as observer member in December 2014. Upgraded to consultative in 2019.
Djibouti	Movement for Democratic Renewal and Development	MRD	in opposition	Admitted as consultative members in 2019.
Gabon	Gabonese Progress Party	PGP	—	Admitted as consultative member in 1996.
Gambia	United Democratic Party	UDP	—	Admitted as consultative member in 2012. Boycotted last election.
Georgia	Social Democrats for the Development of Georgia	SDD	—	Admitted as consultative member in 2013.
Ghana	Convention People's Party	CPP		Admitted as consultative member in 2018
Guinea-Bissau	African Party for the Independence of Guinea and Cape Verde	PAIGC	in government	Admitted as consultative member in 2008.
Iran	Democratic Party of Iranian Kurdistan	PDKI	—	Admitted as observer member in 1996. Promoted to consultative member in 2008.
Palestine	Palestinian National Initiative	PNI	in opposition	Admitted as observer member in 2008. Promoted to consultative member in 2012.
Palestine	Palestine Popular Struggle Front	PPSF		Admitted as consultative member in 2018.
Sahrawi Republic	Polisario Front	POLISARIO	in government	Admitted as observer member in 2008. Promoted to consultative member in 2017.
São Tomé and Príncipe	Movement for the Liberation of São Tomé and Príncipe/Social Democratic Party	MLSTP/PSD	in government	Admitted as consultative member in 2013.
Eswatini	People's United Democratic Movement	PUDEMO	—	Admitted as consultative member in 2013. Political parties are banned in Eswatini.
Syria	Democratic Union Party	PYD		Admitted as consultative member in November 2015.
Togo	Democratic Convention of African Peoples	CDPA		Admitted as consultative member in 1999.
Turkey	Peoples' Democratic Party	HDP	in opposition	Admitted as consultative member in 2015.
Ukraine	Social Democratic Party of Ukraine	SDPU	—	Admitted as consultative member in 2003.

Observer parties

The following parties are observer parties:

Country	Name	Abbr	Government	Notes
Eswatini	Swaziland Democratic Party	SWADEPA		Admitted as observer member in June/July 2014.
Iran	Komala Party of Iranian Kurdistan	KPIK		Admitted as observer member in December 2014.
Iran	Komala Party of Kurdistan	KPK		Admitted as observer member in December 2014.
Kenya	Labour Party of Kenya			Admitted as observer member in 2012.
Kosovo	Self-determination Movement	VV		Admitted as observer member in 2018.
Lesotho	Lesotho Congress for Democracy	LCD	in opposition	Admitted as observer member in June/July 2014.
Serbia	Social Democratic Party of Serbia	SDPS	junior party in coalition government	Admitted as observer member in 2018.
United Kingdom	Labour Party		in opposition	Member since 1951. Welsh Labour is in government in the Welsh Assembly, holds the London Mayoralty and London Assembly. The party asked and obtained to be downgraded to observer status in February 2013 "in view of ethical concerns, and to develop international co-operation through new networks."

Former members

Country	Name	Abbr	Notes
Albania	Social Democratic Party of Albania	PSD	Admitted as consultative member in 1992. Promoted to full member in 1996. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Algeria	National Liberation Front	FLN	Expelled following the 2019 Algerian protests.
Andorra	New Democracy	ND	Admitted as consultative member in 1999.
Antigua and Barbuda	Antigua Labour Party	ALP	Admitted as consultative member in 2008.
Argentina	Popular Socialist Party	PSP	Admitted as full member in 1992. Merged with the Democratic Socialist Party to form the Socialist Party.
Argentina	Socialist Party	PS	Full member since 1951.
Aruba	People's Electoral Movement	MEP	Promoted to full member in 1992. Full member since 1994. Delisted in December 2014.
Australia	Australian Labor Party	ALP	Admitted as full member in 1966. Delisted in December 2014.
Barbados	Barbados Labour Party	BLP	Admitted as full member in 1987. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Belgium	Belgian Socialist Party	PSB/BSP	Founder member. Split in 1978.
Belgium	Socialist Party Different	SP.a	Delisted in 2017.
Benin	Democratic Union of Progressive Forces	UDFP	Admitted as observer member in 1992.
Benin	Social Democratic Party	PSD	Admitted as consultative member in 1999. Promoted to full member in 2003.
Bosnia and Herzegovina	Alliance of Independent Social Democrats	SNSD	Admitted as consultative member in 2003. Promoted to full member in 2008 Expelled in August 2012.
Botswana	Botswana National Front	BNF	Admitted as observer member in 1996.
Bolivia	Revolutionary Left Movement	MIR	Admitted as consultative member in 1986. Consultative member in 1987. Promoted to full member in 1992.
Bulgaria	European Left	BEL	Admitted as observer member in 1999.
Burkina Faso	Party for Democracy and Progress / Socialist Party	PDP/PS	Admitted as full member circa 1995. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Burundi	Front for Democracy in Burundi	FRODEBU	Admitted as consultative member in 2003. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Canada	Co-operative Commonwealth Federation	CCF	Became the New Democratic Party in 1961.
Canada	New Democratic Party	NDP/NPD	Delisted in 2018.
Central African Republic	Movement for Democracy and Social Progress	MDPS	Admitted as observer member in 1992.
Ivory Coast	Ivorian Popular Front	FPI	Admitted as consultative member in 1992. Promoted to full member in 1996. Expelled in March 2011.
Colombia	Alternative Democratic Pole	PDA	Former observer member. Delisted in December 2014.
Colombia	M-19 Democratic Alliance		Admitted as observer member in 1992.
Curaçao	Partido MAN	MAN	Promoted to full member in 1989. Delisted in 2017.
Denmark	Social Democrats	SD	Founding member. Withdrew in 2017.
Dominica	Dominica Labour Party	DLP	Admitted as consultative member in 1996. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Ecuador	Democratic Left	PID	Member since 1987. Delisted in 2017.
Egypt	Egyptian Social Democratic Party	ESDP (or HMDI in Arabic)	Admitted as consultative member in 2012. Promoted to full member in November 2015. Delisted in 2019 due to non-payment of membership fees.
Egypt	National Democratic Party	NDP	Admitted as full member in 1989. Full member since 1992. Expelled in January 2011.
El Salvador	Democratic Party	PD	Admitted as observer member in 1996.
Estonia	Social Democratic Party	SDE	Member since 1990. Withdrew in 2017.
Fiji	Fiji Labour Party	FLP	Admitted as consultative member in 1992. Expelled in 2008, due to the party's participation in a government issued from a military coup.
Georgia	Union of Citizens of Georgia	CUG	Admitted as observer member in 1996.
Germany	Social Democratic Party of Germany	SPD	Founding member. Withdrew in 2017.
Greenland	Forward		Admitted as consultative member in 1986. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Guatemala	Social Democratic Convergence	CSD	Admitted as consultative member in 2003.
Haiti	Party of the National Congress of Democratic Movements	KONAKOM	Admitted as consultative member in 1992. Promoted to full member in 1996.
Haiti	Struggling People's Organization	OPL	Admitted (as Lavalas Political Organisation) as observer member in 1996.
Haiti	Revolutionary Progressive Nationalist Party	PANPRA	Admitted as consultative member in 1989. Promoted to full member in 1992.
Hungary	Social Democratic Party of Hungary	MSZDP	Member since 1990. Admitted as observer member in 1992. Promoted to consultative member in 1999. Promoted to full member in 2003.
Iceland	Social Democratic Party	A	Member since 1987. Formed Social Democratic Alliance in 2000.
Iceland	Social Democratic Alliance	S	Withdrew in 2017.
Iran	League of Iranian Socialists		Joined in 1960. It was dissolved in 1980s.
Italy	Democratic Party of the Left	PDS	Admitted as full member in 1992. Merged with others to form Democrats of the Left in 1998.
Italy	Democrats of the Left	DS	Full member since 1992 as Democratic Party of the Left. Merged with other movements to form the Democratic Party in 2007. Listed as SI member until XXIV Congress in 2012.
Italy	Italian Socialist Party	PSI	Party dissolved in 1994 and succeeded by the Italian Socialists (who formed the Italian Democratic Socialists in 1998 and resumed as the Italian Socialist Party PSI in 2007).
Italy	Italian Democratic Socialist Party	PSDI	Party merged into the Italian Democratic Socialists in 1998 (renamed into Italian Socialist Party PSI in 2007).
Japan	Democratic Socialist Party	Minsha-tō	Admitted as SI member in 1961. Merged with non-socialist movements to form the New Frontier Party in 1994.
Jordan	Jordanian Democratic Party of the Left	JDPL	Admitted as observer member in 2003.
Kyrgyzstan	Ata Meken Socialist Party		Admitted as observer member in 2008.
Latvia	Latvian Social Democratic Workers' Party	LSDSP	Full member since 1994. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Latvia	Social Democratic Party "Harmony"	SDPS	Admitted as consultative member in June/July 2014. Withdrew in 2017.
Luxembourg	Luxembourg Socialist Workers' Party	LSAP/POSL	Full member since 1951. Delisted in 2018 for non-payment of membership fees.
North Macedonia	Social Democratic Union of Macedonia	SDSM	Admitted as observer member in 1996. Promoted to full member in 2003. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Madagascar	Party for National Unity	VITM	Admitted as consultative member in 1989.
Malaysia	Democratic Action Party	DAP	Full member since 1987. Delisted in 2017.
Malta	Labour Party	PL	Full member since 1955. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Mexico	Party of the Democratic Revolution	PRD	Admitted as full member in 1996.
Moldova	Social Democratic Party of Moldova	PSDM	Admitted as observer member in 1996.
Namibia	Congress of Democrats	CoD	Admitted as consultative member in 2003. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Netherlands	Labour Party	PvdA	Decided to minimise involvement in SI in December 2012. Delisted in December 2014.
New Zealand	New Zealand Labour Party	NZLP	Member since 1952. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Nicaragua	Sandinista National Liberation Front	FSLN	Expelled in January 2019 because of violation of human rights during the Nicaraguan protests
Nigeria	All Progressives Congress	APC	Admitted as consultative member in December 2014.
North Vietnam	Vietnamese Socialist Party		Consultative member between 1955 and 1969.
Norway	Labour Party	DNA	Member since 1951. Withdrew in 2016.
Paraguay	Party for a Country of Solidarity	PPS	Admitted as consultative member in 2003. Promoted to full member in 2008.
Paraguay	Revolutionary Febrerista Party	PRF	Admitted as full member in the 1970s.
Philippines	Akbayan Citizens' Action Party	AKBAYAN	Admitted as consultative member in 2003.
Poland	Democratic Left Alliance	SLD	Full member since 1996. Withdrew in 2017.
Poland	Labour Union	UP	Admitted as full member in 1996. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Poland	Social Democracy of the Republic of Poland	SdRP	Admitted as full member in 1996. Absorbed into the Democratic Left Alliance in 1999.
Romania	Democratic Party	PD	Admitted as consultative member in 1996. Promoted to full member in 1999. Merged with the Liberal Democratic Party to form the Democratic Liberal Party.
Russia	Social Democratic Party of Russia	SDPR	Admitted as consultative member in 2003.
Saint Lucia	Progressive Labour Party		Expelled in 1992.
Saint Kitts and Nevis	Saint Kitts and Nevis Labour Party	SKNLP	Admitted as consultative member in 1992. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Saint Lucia	Saint Lucia Labour Party	SLP	Admitted as consultative member in 1992. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Saint Vincent and the Grenadines	Saint Vincent Labour Party	SVGLP	Admitted as consultative member in 1989. Merged with the Movement for National Unity in 1994 to form the Unity Labour Party.
Saint Vincent and the Grenadines	Unity Labour Party	ULP	Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Serbia	Democratic Party	DS	Admitted as consultative member in 2003. Promoted to full member in 2008.
Serbia	Social Democratic Party	SDP	Admitted as consultative member in 2003. Promoted to full member in 2008. Demoted to observer member in 2012 due to non-payment of membership fees. Ceased to exist in 2009
Singapore	People's Action Party	PAP	Resigned in 1976 due to Dutch concerns over suppression of free speech.
Slovakia	Party of the Democratic Left	SDĽ	Admitted as full member in 1996. Merged with Direction – Social Democracy in 2005.
Slovakia	Social Democratic Party of Slovakia	SDSS	Admitted as full member in 1992. Merged with Direction – Social Democracy in 2005.
Slovenia	Slovenian Democratic Party	SDS	Admitted (as the Social Democratic Party of Slovenia) as observer member in 1992.
Slovenia	Social Democrats	SD	Admitted (as United List of Social Democrats) as full member in 1996. Demoted to observer member in 2012 due to non-payment of membership fees. Delisted in December 2014.
Sweden	Swedish Social Democratic Party	SAP	Withdrew in March 2017.
Switzerland	Social Democratic Party of Switzerland	SP/PS	Withdrew in 2017.
Tanzania	Chama Cha Mapinduzi	CCM	Admitted as full member in 2013.
Timor-Leste	Revolutionary Front for an Independent East Timor	FRETILIN	Admitted as consultative member in 2003.
Tunisia	Constitutional Democratic Rally	RCD	Admitted as full member in 1989. Full member since 1993. Expelled in January 2011.
Tunisia	Popular Unity Movement	MUP	Admitted as consultative member in 1989.
Turkey	Democratic Left Party	DSP	Admitted as consultative member in 1986. Expelled in 1992.
Turkey	Democratic People's Party	DEHAP	Admitted as observer member in 2003. Merged with the Democratic Society Movement to form the Democratic Society Party which in turn was succeeded by the Peace and Democracy Party.
Turkey	Social Democracy Party	SODEP	Full member since 1990. Merged with the Republican People's Party in 1995.
Turkey	Social Democratic Populist Party	SHP	Admitted as consultative member in 1986. Promoted to full member in 1989. Merged with the Republican People's Party in 1995.
Ukraine	Socialist Party of Ukraine	SPU	Admitted as consultative member in 2003. Expelled in July 2011.
United States	Democratic Socialists of America	DSA	Had been a member of SI since founding in 1982, withdrew in August 2017.
United States	Social Democrats, USA	SDUSA	Member since 1972. Withdrew in 2005.
Uruguay	Party for the Government of the People	PGP	Admitted as consultative member in 1992. Merged with the Colorado Party in 1994.
Uruguay	Socialist Party of Uruguay	PSUA	Admitted as full member in 1999. Withdrew in 2017.
Venezuela	For Social Democracy	PODEMOS	Admitted as consultative member in 2008.
Venezuela	Movement for Socialism	MAS	Admitted as consultative member in 2003.
Zambia	Patriotic Front	PF	Admitted as consultative member in 2013.
Zimbabwe	Movement for Democratic Change	MDC	Admitted as full member in 2008. Delisted in 2017.

• International Falcon Movement - Socialist Education International
• International Union of Socialist Youth
• Socialist International Women

• International Federation of the Socialist and Democratic Press
• International Labour Sports Confederation
• International League of Religious Socialists
• International Union of Social Democratic Teachers
• Jewish Labour Bund
• National Democratic Institute for International Affairs
• Parliamentary Group of the Party of European Socialists
• Party of European Socialists
• Social Democratic Group of the Latin American Parliament
• World Labour Zionist Movement

• African Socialist International
• PARLATINO