The Social Democratic Workers' Party of Germany (, abbreviated as SDAP) was a Marxist socialist political party in the North German Confederation during the period of unification. Founded in Eisenach in 1869, the SDAP endured through the early years of the German Empire. Often termed the Eisenachers, the SDAP was one of the first political organizations established among the nascent German labor unions of the nineteenth century. It officially existed under the name SDAP for only six years (1869–1875), but through name changes and political partnerships its lineage can be traced to the present-day Social Democratic Party of Germany.