The Hallstein Doctrine, named after Walter Hallstein, was a key doctrine in the foreign policy of the Federal Republic of Germany (West Germany) after 1955. It established that the Federal Republic would not establish or maintain diplomatic relations with any state that recognized the German Democratic Republic (GDR, East Germany). Important aspects of the doctrine were abandoned after 1970 when it became difficult to maintain and the Federal government changed its politics towards the GDR.

Following Germany's defeat in World War II, the territory east of the Oder-Neisse Line was under Soviet or Polish administration and had de facto been annexed. The rest of the territory was divided into four occupation zones controlled by the Allies, with the former capital, Berlin, being similarly divided into four sectors. The western zones controlled by France, the United Kingdom, and the United States were merged, in May 1949, to form the Federal Republic of Germany (Bundesrepublik Deutschland); in October 1949, the Soviet Zone became the German Democratic Republic (Deutsche Demokratische Republik, or DDR). They were informally known as "West Germany" and "East Germany". However, prior to 1954, the Allies still officially retained responsibility for the whole of Germany and neither East Germany nor West Germany had regained their sovereignty.