The German invasion of Greece, also known as the Battle of Greece or Operation Marita, was the attacks on Greece by Italy and Germany during World War II. The Italian invasion in October 1940, which is usually known as the Greco-Italian War, was followed by the German invasion in April 1941. German landings on the island of Crete came after Allied forces had been defeated in mainland Greece. These battles were part of the greater Balkans Campaign of the Axis powers and their associates.

Nazi Germany, officially known as the German Reich and later the Greater German Reich, is a term used to describe the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a totalitarian dictatorship. The Third Reich, meaning "Third Realm" or "Third Empire", referred to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which the Nazis referred to as the Thousand-Year Reich, ended in May 1945, after only 12 years, when the Allies defeated Germany and entered the capital, Berlin, ending World War II in Europe.