Organisation Consul (O.C.) was an ultra-nationalist and anti-Semitic terrorist organization that operated in the Weimar Republic from 1920 to 1922. It was formed by members of the disbanded Freikorps group Marine Brigade Ehrhardt and was responsible for political assassinations that had the ultimate goal of destroying the Republic and replacing it with a right-wing dictatorship. Its two most prominent victims were the former finance minister Matthias Erzberger and Foreign Minister Walther Rathenau. The group was banned by the German government in 1922.

The Weimar Republic, officially known as the German Reich, was a historical period of Germany from 9 November 1918 to 23 March 1933, during which it was a constitutional federal republic for the first time in history; hence it is also referred to, and unofficially proclaimed itself, as the German Republic. The period's informal name is derived from the city of Weimar, which hosted the constituent assembly that established its government. In English, the republic was usually simply called "Germany", with "Weimar Republic" not commonly used until the 1930s.