The Abwehr was the German military-intelligence service for the Reichswehr and the Wehrmacht from 1920 to 1945. Although the 1919 Treaty of Versailles prohibited the Weimar Republic from establishing an intelligence organization of their own, they formed an espionage group in 1920 within the Ministry of Defence, calling it the Abwehr. The initial purpose of the Abwehr was defense against foreign espionage: an organizational role that later evolved considerably. Under General Kurt von Schleicher the individual military services' intelligence units were combined and, in 1929, centralized under Schleicher's Ministeramt within the Ministry of Defence, forming the foundation for the more commonly understood manifestation of the Abwehr.

The Oberkommando der Wehrmacht was the supreme military command and control office of Nazi Germany during World War II. Created in 1938, the OKW replaced the Reich Ministry of War and had oversight over the individual high commands of the country's armed forces: the army, navy, and air force.