Walther Gustav Reinhardt was a German officer who served as the last Prussian Minister of War and the first head of the army command within the newly created Ministry of the Reichswehr of the Weimar Republic. During the Kapp Putsch of 1920, Reinhardt remained loyal to the elected government and was one of the few senior officers of the Reichswehr willing to order troops to fire at the revolting units.

The Ministry of the Reichswehr was the defence ministry of the Weimar Republic and the early Third Reich. The 1919 Weimar Constitution provided for a unified, national ministry of defence to coordinate the new Reichswehr, and that ministry was set up in October 1919, from the existing Prussian War Ministry and Reichsmarineamt. It was based in the Bendlerblock building. The Wehrgesetz of 21 May 1935 renamed it the Reich Ministry of War, which was then abolished in 1938 and replaced with the Oberkommando der Wehrmacht.