The Marinebrigade Ehrhardt, also known as the Ehrhardt Brigade, was a Freikorps unit of the early Weimar Republic. It was formed on 17 February 1919 as the Second Marine Brigade from members of the former Imperial German Navy under the leadership of Hermann Ehrhardt. The Brigade was used primarily in the suppression of the Bavarian Soviet Republic and the First Silesian Uprising, both in the first half of 1919. In March 1920, faced with its imminent disbanding by orders of the government in Berlin, the Marine Brigade was one of the main supporters of the Kapp Putsch that tried to overthrow the Weimar Republic. After the putsch failed and the Brigade was disbanded in May, many of the former members formed the secret Organisation Consul under Ehrhardt's leadership. Before it was banned in 1922, it carried out numerous assassinations and murders in a continuation of the attempts to overthrow the Republic.

Hermann Ehrhardt was a German naval officer in World War I who became an anti-republican and anti-Semitic German nationalist Freikorps leader during the Weimar Republic. As head of the Marine Brigade Ehrhardt, he was among the best-known Freikorps leaders in the immediate postwar years. The Brigade fought against the local soviet republics that arose during the German Revolution of 1918–1919 and later was among the key players in the anti-democratic Kapp Putsch of March 1920. After the Brigade's forced disbanding, Ehrhardt used the remnants of his unit to found the Organisation Consul, a secret group that committed numerous politically motivated assassinations. After it was banned in 1922, Ehrhardt formed other less successful groups such as the Bund Viking. Because of his opposition to Adolf Hitler, Ehrhardt was forced to flee Germany in 1934 and lived apolitically in Austria until his death in 1971.