Martin Eugen Ekström (6 December 1887 – 28 December 1954) was a Swedish military adventurer who became the leader of the National Socialist Bloc, an umbrella organization for various fascist and National Socialist groups. Ekström was born in By, Avesta Municipality. During the 1918 Finnish Civil War, he led the Vasa Regiment which was responsible of the Vyborg massacre. Lieutenant colonel Ekström led the 3rd Battlegroup of the Swedish Volunteer Corps in the Finnish Winter War. He died in Helsinki, aged 67.