The Reichstag of the Weimar Republic (1919–1933) was the lower house of Germany's parliament; the upper house was the Reichsrat, which represented the states. The Reichstag convened for the first time on 24 June 1920, taking over from the Weimar National Assembly, which had served as an interim parliament following the collapse of the German Empire in November 1918.

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.