Social Democracy

Chairperson: Josef Boleslav Pecka (1878–1893) Josef Hybeš (1887–1893) Josef Steiner (1893–1904) Antonín Němec (1904–1915) Bohumír Šmeral (1916–1917) Antonín Němec (1917–1925) Antonín Hampl (1925–1938) Zdeněk Fierlinger (1945–1947) Bohumil Laušman (1947–1948) Blažej Vilím (1948, in exile) Václav Majer (1948–1972, in exile) Vilém Bernard (1972–1989, in exile) Karel Hrubý (1989, in exile) Slavomír Klaban (1989–1990) Jiří Horák (1990–1993) Miloš Zeman (28 February 1993 – April 2001) Vladimír Špidla (April 2001 – 26 July 2004) Stanislav Gross (26 July 2004 – 26 April 2005) Bohuslav Sobotka (2005–2006; acting) Jiří Paroubek (2006–2010) Bohuslav Sobotka (2011–2017) Milan Chovanec (2017–2018; acting) Jan Hamáček (2018–2021) Roman Onderka (2021; acting) Michal Šmarda (2021–2024) Jana Maláčová (2024–2025) Jiří Nedvěd (since 13 December 2025)