James (Big Jim) Larkin (Irish: Séamas Ó Lorcáin; 21 January 1876 – 30 January 1947), was an Irish trade union leader and socialist activist, born to Irish parents in Liverpool, England in 1875. He and his family later moved to a small cottage in Burren, southern County Down. Growing up in poverty, he received little formal education and began working in a variety of jobs while still a child. He became a full-time trade union organiser in 1905.
In early 1913, Larkin achieved some notable successes in industrial disputes in Dublin; these involved frequent recourse to sympathetic strikes and blacking (boycotting) of goods. Two major employers, Guinness and the Dublin United Tramway Company, were the main targets of Larkin's organising ambitions. Both had craft unions for skilled workers, but Larkin's main aim was to unionise the unskilled workers as well.