| Abbr. | Logo | Ideology | Founded | Founder | Leader | Website | European Parliament Group |
| LSAP |  | Social democracy, Progressivism, Pro-Europeanism | 1945 | Francine Closener Dan Biancalana | http://www.lsap.lu |  |
Elections
| Date | Elections | % | Votes | Seats | |
| 2023 | 18,91 | 711.890 | 11 | 2nd | |
| 2019 | EU | 12,19 | 152.900 | 1 | 4th |
| 2018 | 17,60 | 621.332 | 10 | 2nd | |
| 2014 | EU | 11,73 | 137.504 | 1 | 4th |
| 2013 | 20,28 | 662.343 | 13 | 2nd | |
| 2009 | 23,00 | 695.830 | 13 | 2nd | |
| 2009 | EU | 19,49 | 218.532 | 1 | 2nd |
| 2004 | 25,44 | 785.490 | 14 | 2nd | |
| 2004 | EU | 22,09 | 239.967 | 1 | 2nd |
| Leaders | |
| 1945 – 1951 | Michel Rasquin |
| 1951 – 1952 | Paul Wilwertz |
| 1952 – 1954 | Albert Bousser |
| 1954 – 1955 | Émile Ludwig |
| 1955 – 1959 | Paul Wilwertz |
| 1959 – 1970 | Henry Cravatte |
| 1970 – 1974 | Antoine Wehenkel |
| 1974 – 1980 | Lydie Schmit |
| 1980 – 1985 | Robert Krieps |
| 1985 – 1997 | Ben Fayot |
| 1997 – 2004 | Jean Asselborn |
| 2004 – 2014 | Alex Bodry |
| 2014 – 2019 | Claude Haagen |
| 2019 – 2020 | Franz Fayot |
| 2020 – 2022 | Yves Cruchten |
| 2022 – | Francine Closener and Dan Biancalana |
