The occupation of Greece by the Axis Powers (Greek: Η Κατοχή, I Katochi, meaning "The Occupation") began in April 1941 after Nazi Germany invaded Greece to assist its ally, Fascist Italy, which had been at war with Greece since October 1940. Following the conquest of Crete, all of Greece was occupied by June 1941. The occupation in the mainland lasted until Germany and its ally Bulgaria were forced to withdraw under Allied pressure in early October 1944. However, German garrisons remained in control of Crete and some other Aegean islands until after the end of World War II in Europe, surrendering these islands in May and June 1945.
Fascist Italy had initially declared war and invaded Greece in October 1940, but the Hellenic Army initially managed to push back the invading forces into neighboring Albania, then an Italian protectorate. Nazi Germany was forced to an intervention on its ally's behalf in southern Europe. While most of the Hellenic Army was dislocated on the Albanian front to fend off the Italian counter-attacks, a rapid German Blitzkrieg campaign commenced in April 1941, and by June Greece was defeated. As result, the Greek government went into exile, and an Axis collaborationist puppet government was established in the country. Furthermore, Greece's territory was divided into occupation zones run by the Axis powers, with the Germans proceeding to administer the most important regions of the country themselves, including Athens, Thessaloniki and the most strategic Aegean Islands. Other regions of the country were given to Germany's partners, Italy and Bulgaria.