Hugo Dewar (9 August 1908 – June 1980) was an author, poet, and political activist influential in co-founding two of the earliest British Trotskyist groups. Dewar was born in Leyton in London in 1908. He joined the Independent Labour Party in 1928, and in 1930 co-founded the (aka Marxist League). He joined the Communist Party of Great Britain in 1931, but was expelled the following year. He was one of the founders in 1932 of the Communist League, and remained active in International Left Opposition groups until he was drafted into the army in 1943. He worked as an adult education tutor.