Gustav Adolf Bauer (6 January 1870 – 16 September 1944) was a German Social Democratic Party leader and the chancellor of Germany from June 1919 to March 1920. Prior to that, he was minister of labour in the last cabinet of the German Empire and during most of the German Revolution that preceded the formal establishment of the Weimar Republic.
Bauer became minister president of the Weimar National Assembly in June 1919 after Philipp Scheidemann resigned in protest against the Treaty of Versailles. Following the adoption of the Weimar Constitution in August 1919, Bauer's title formally changed to "chancellor".