East Germany (German: Ostdeutschland), officially the German Democratic Republic (GDR; Deutsche Demokratische Republik, pronounced [ˈdɔʏtʃə demoˈkʁaːtɪʃə ʁepuˈbliːk] (listen), DDR, pronounced [ˌdeːdeːˈʔɛʁ] (listen)), was a country in Central Europe that existed from its creation on 7 October 1949 until its dissolution on 3 October 1990. Until 1989, this country was commonly viewed as a communist state, and it described itself as a socialist "workers' and peasants' state". Before the establishment, its territory was administered and occupied by Soviet forces with the autonomy of the native communists following the Berlin Declaration abolishing German sovereignty in World War II; when the Potsdam Agreement established the Soviet-occupied zone, bounded on the east by the Oder–Neisse line. The GDR was dominated by the Socialist Unity Party of Germany (SED) from 1949 to 1989 before being liberalized under the impact of the Revolutions of 1989 against the communist states, helping East Germany be united with the West. Unlike West Germany, SED did not see its state as the successor one of the German Reich (1871–1945) and abolished the goal of unification in the constitution (1974). Under the SED rule, GDR was often judged as a Soviet satellite state; most scholars and academics described it as a totalitarian regime.

The GDR was established in the Soviet-occupied zone of former Nazi Germany (1933–1945) of the German Reich on 7 October 1949, while the Federal Republic of Germany (FRG) (preceded by the fragmentary self-governance of West German politicians), commonly referred to as West Germany, was established in the three Western US–UK–French occupied zones before. It was a satellite state of the Soviet Union. Soviet occupation authorities began transferring administrative responsibility to German communist leaders in 1948 and the GDR began to function as an independent state on 7 October 1949, gaining sovereignty from the Soviet Union in 1955, although the Soviet Union was still deeply involved in this country's situation. In 1972, East Germany was recognized by West Germany and vice versa as well as these two German independent countries together became two separate members of the United Nations the following year. Until 1989, the GDR was governed by the Socialist Unity Party of Germany, a communist party founded in the Soviet-occupied zone in 1946; although other parties nominally participated in its alliance organization, the National Front of the German Democratic Republic. The SED made the teaching of Marxism–Leninism and the Russian language compulsory in schools in the GDR.

The economy of this country was centrally planned and state-owned. Prices of housing, basic goods and services were heavily subsidized and set by central government planners rather than rising and falling through supply and demand. Although the GDR had to pay substantial war reparations to the Soviets, it became the most successful economy in the Eastern Bloc. Emigration to the West was a significant problem as many of the emigrants were well-educated young people; such emigration weakened the state economically. In response, the GDR government fortified its inner German border and later built the Berlin Wall in 1961. Many people attempting to flee were killed by border guards or booby traps such as landmines. Those captured spent long periods of time imprisoned for attempting to escape. In 1951, a referendum in the GDR regarding the remilitarization of Germany was held, with 95% of the population voting in favour.

In 1989, numerous social, economic and political forces in the GDR and abroad, one of the most notable being peaceful protests starting in the city of Leipzig, led to the fall of the Berlin Wall and the establishment of a government committed to liberalization. The following year, a free and fair election was held in the country and international negotiations between four occupation Allied countries and two German countries led to the signing of the Final Settlement treaty to replace the Potsdam Agreement on the status and border of future-reunited Germany. The GDR ceased to exist when its five states ("Länder") joined the Federal Republic of Germany under Article 23 of the Basic Law and its East Berlin was also united with West Berlin into a single city of the FRG, on 3 October 1990. Several of the GDR's leaders, notably its last communist leader Egon Krenz, were later prosecuted for offenses committed during the GDR's times.

Geographically, the GDR bordered the Baltic Sea to the north, Poland to the east, Czechoslovakia to the southeast and West Germany to the southwest and west. Internally, the GDR also bordered the Soviet sector of Allied-occupied Berlin, known as East Berlin, which was also administered as the country's de facto capital. It also bordered the three sectors occupied by the United States, United Kingdom, and France known collectively as West Berlin (de facto part of the FRG). The three sectors occupied by the Western countries were sealed off from the GDR by the Berlin Wall from its construction in 1961 until it was opened in 1989 as part of the Peaceful Revolution against East Germany.