Socialist League may refer to one of several organizations.

• See Socialist League (Britain) for information on several British groups which have operated under that name. One founded in 1885 by William Morris and Ernest Belfort Bax and existed until 1901; another founded in the 1932 by Stafford Cripps existed until 1937, and a third which was founded in 1981 by former members of the International Marxist Group was better known as Socialist Action.

• Socialist League in Finland is a Trotskyist organization affiliated with the International Socialist Tendency

• Socialist League in Canada was a Trotskyist group founded in 1974 by Ross Dowson and was better known by the name of its newpaper, Forward

• The Socialist League of Palestine was founded in 1936 by Hashomer Hatzair. The party was commonly referred to as Hashomer Hatzair until 1948 when it merged with other left wing elements to become Mapam.