Reichswehr was the official name of the German armed forces during the Weimar Republic and the first years of the Third Reich. After Germany was defeated in World War I, the Imperial German Army was dissolved in order to be reshaped into a peacetime army. From it a provisional Reichswehr was formed in March 1919. Under the terms of the Treaty of Versailles, the rebuilt German Army was subject to severe limitations in size, structure and armament. The official formation of the Reichswehr took place on 1 January 1921 after the limitations had been met. The German armed forces kept the name Reichswehr until Adolf Hitler's 1935 proclamation of the "restoration of military sovereignty", at which point it became part of the new Wehrmacht.

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.