Iron Wolf (Lithuanian: Geležinis Vilkas) was a semi-official Lithuanian militarized organization active in 1928–1930, led by Prime Minister Augustinas Voldemaras. Established at the end of 1927 by the ruling Lithuanian Nationalist Union to help suppress its opposition, it was inspired by the Blackshirts, an Italian fascist organization. The organization was secret; it was officially a sports union from May 1928. The organization spied on its political opponents, engaged in limited physical coercion, and launched propaganda initiatives. It had more than 4,000 members.
When Voldemaras was removed as Prime Minister in September 1929, Antanas Smetona attempted to install his men. When that failed, the organization was officially closed on 24 May 1930. However, supporters of Voldemaras remained active and became known as Voldemarininkai ("Voldemarians", "Voldemarists"). They planned several anti-Smetona coups, became increasingly sympathetic to fascism, and often collaborated with Nazis during the German occupation of Lithuania. Iron Wolf was briefly reestablished in 1941 to support the pro-Nazi Lithuanian Nationalist Party .