Gustav Adolf Bauer (listenⓘ; 6 January 1870 – 16 September 1944) was a German Social Democratic Party leader and the chancellor of Germany from June 1919 to March 1920.

Bauer became minister president of the Weimar National Assembly in June 1919 after Philipp Scheidemann resigned in protest against the Treaty of Versailles.

During his term of office, a crucial tax restructuring was enacted, as were a series of important social reforms that affected unemployment relief, maternity benefits and health and old age insurance.

He also was editor of the publication Der Büroangestellte ("The Office Worker") and in 1903 was named head of the Central Labour Secretariat of the Free Trade Unions in Berlin.

[1] In 1912, Bauer was elected to the Reichstag for the Social Democratic Party of Germany (SPD) in a constituency of Breslau in the Prussian province of Silesia.

In October 1918, he became state secretary (similar to a minister) in the Ministry of Labour in the cabinet of Max von Baden,[1] a position he remained in throughout the Revolution of 1918/19.

On 12 November the Council issued an appeal "To the German People" that included a number of promises related to labour, notably the introduction of the eight-hour workday and the creation and protection of jobs.

In the following weeks, the Council issued decrees regulating the hiring, dismissal and pay of industrial workers, including war invalids and demobilised military personnel.

[4] In February, he became minister of labour in Philipp Scheidemann's cabinet, Germany's first democratically elected national government.

After Scheidemann resigned on 20 June 1919 in protest against the terms of the Treaty of Versailles, both Eduard David and Hermann Müller of the Social Democrats refused the offer to succeed him as minister president.

[7] Some of the most far-reaching changes implemented during Bauer's term of office were the tax reform packages developed by Finance Minister Matthias Erzberger.

The Reich Revenue Law of July 1919 gave the federal government sole authority for levying and administering taxes, unlike under the Empire when the states had control.