Full member parties
| Albania | |
|---|---|
| Algeria | |
| Andorra | |
| Angola | |
| Argentina | |
| Armenia | |
| Azerbaijan | |
| Belarus | |
| Belgium | |
| Bolivia | |
| Bosnia and Herzegovina | |
| Brazil | |
| Bulgaria | |
| Burkina Faso | |
| Cabo Verde | |
| Cameroon | Social Democratic Front, SDF |
| Chad | |
| Chile | |
| Colombia | |
| Costa Rica | |
| Croatia | |
| Cyprus | |
| Czech Republic | |
| Democratic Republic of Congo | |
| Dominican Republic | |
| Ecuador | |
| Equatorial Guinea | |
| Finland | |
| France | |
| Ghana | |
| Greece | |
| Guatemala | |
| Guinea | |
| Haiti | |
| Hungary | |
| India | |
| Iran | |
| Iraq | |
| Israel | |
| Italy | |
| Jamaica | |
| Japan | |
| Kazakhstan | |
| Kyrgyzstan | |
| Lithuania | |
| Lebanon | |
| Mali | African Party for Solidarity and Justice, ADEMA-PASJ |
| Mauritania | Assembly of Democratic Forces, RFD |
| Mauritius | Mauritius Labour Party |
| Mexico | |
| Republic of Moldova | |
| Mongolia | |
| Montenegro | |
| Morocco | |
| Mozambique | |
| Namibia | |
| Nepal | |
| Niger | |
| Pakistan | |
| Palestine | |
| Paraguay | |
| Panama | |
| Peru | |
| Philippines | Philippines Social Democratic Party, PDSP |
| Portugal | |
| Puerto Rico | |
| Romania | |
| San Marino | |
| Senegal | |
| Slovakia | |
| South Africa | |
| Spain | |
| Tunisia | |
| Turkey | |
| Uruguay | |
| Venezuela | <a href="https://www.facebook.com/partidoUNT">A New Era, UNT |
| Yemen |
Consultative parties
| Botswana | Botswana Democratic Party, BDP |
|---|---|
| Democratic Republic of Congo | Unified Lumumbist Party, PALU |
| Djibouti | |
| Eswatini | |
| Gabon | Gabonese Party for Progress, PGP |
| Gambia | |
| Georgia | Social Democrats for Development, SDD |
| Ghana | Convention People's Party, CPP |
| Guinea-Bissau | African Party of Independence of Guinea and Cape Verde, PAIGC |
| Iran | |
| Palestine | Palestinian National Initiative, PNI |
| São Tomé and Príncipe | Movement for the Liberation of São Tomé and Príncipe/Social Democratic Party, MLSTP-PSD |
| Syria | |
| Togo | Democratic Convention of African Peoples, CDPA |
| Turkey | |
| Ukraine | |
| Western Sahara |
Observer parties
| Eswatini | |
|---|---|
| Great Britain and Northern Ireland | |
| Great Britain and Northern Ireland | Social Democratic and Labour Party, SDLP of Northern Ireland |
| Ireland | |
| Kenya | |
| Kosovo | |
| Lesotho | |
| Serbia | |
| Somaliland | Justice and Welfare Party, JWP |
Associated organisations
| Euro-Latin American Forum of Progressive and Socialist Parliamentarians |
|---|
| International Federation of the Socialist and Democratic Press, IFSDP |
| International Social Democratic Union for Education, ISDUE |
| Jewish Labour Bund, JLB |
| National Democratic Institute for International Affairs, NDI |
| Social Democratic Group of the Latin American Parliament |
| World Labour Zionist Movement, WLZM |