Kullervo Achilles Manner (; 12 October 1880 – 15 January 1939) was a Finnish politician and journalist, and later a Soviet politician. He was a member of the Finnish parliament, serving as its Speaker in 1917. He was also chairman of the Social Democratic Party of Finland between 1917 and 1918. During the Finnish Civil War, he led the Finnish People's Delegation, a leftist alternative to the established Finnish government. After the war, he escaped to the Soviet Union, where he co-founded the Finnish Communist Party. It is said if the Red Guards had won the Civil War, Manner might have risen to the position of the "Leader of the Red Finland".