Curt Theodore Geyer (19 November 1891 – 24 June 1967) was a German socialist politician, historian and journalist. Born in Leipzig, Geyer was the son of Friedrich Geyer, a prominent social democrat. Geyer followed his father in joining the Social Democratic Party of Germany (SPD), and studied history at university, receiving a doctorate in 1914. He became a newspaper editor on various local SPD publications, but he opposed World War I and so joined the Independent Social Democratic Party of Germany (USPD), losing his job. He found work with the Leipziger Volkszeitung, and was the USPD's leading figure in the city during the German Revolution of 1918-1919. He was active in the Workers' and Soldiers' Congress, and won election to the Weimar National Assembly, and then the Reichstag.