Socialist Unity Party of Germany

The Socialist Unity Party of Germany (German: Sozialistische Einheitspartei Deutschlands, SED), in English widely referred to as the East German Communist Party, was the governing party of the German Democratic Republic (East Germany, GDR) from the formation of the Republic on 7 October 1949 until the 1989 revolution, which culminated in the free elections of March 1990. The SED was a communist party with a Marxist-Leninist ideology, considered to be Stalinist in the first years of the GDR's existence. Under its rule, the GDR functioned nominally as a multi-party state with elections that were neither free nor fair, with the SED playing a central leadership role. Other parties in alliance with the SED were the Christian Democratic Union, the Liberal Democratic Party, the Democratic Farmers' Party, and the National Democratic Party. In the 1980s, the SED rejected the policies of Soviet leader Mikhail Gorbachev, such as perestroika and glasnost, maintaining its central role in governing the state. The Party maintained this stance until the collapse of the GDR in the autumn of 1989.

The party's dominant figure from 1950 to 1971, and effective leader of East Germany, was Walter Ulbricht. He was succeeded by Erich Honecker, who only stepped down during the 1989 revolution. The party's last leader, Egon Krenz, was unsuccessful in his attempt to retain the SED's hold on political governance the GDR, and was sentenced to prison after the German reunification.

East Germany was viewed as an illegitimate Stalinist puppet state by much of the population, and the SED party was regularly referred to as "the Russian party."

On 16 December 1989, the SED was dissolved and refounded as the Party of Democratic Socialism abandoning Marxism-Leninism and becoming a mainstream democratic left party. In 2007, the party merged into The Left.