The Socialist League was a socialist organisation in the United Kingdom.
It formed in the 1932 as a split from the Independent Labour Party, opposed to that organisation disaffiliating from the Labour Party. It was led by Stafford Cripps. The League argued for drastic action to be taken by a future Labour government to implement socialist policies. Among the members of the SL were Michael Foot and Barbara Betts (later Barbara Castle).
It was dissolved in 1937 when it was proscribed by Labour, after embarking on a joint campaign with the ILP and the Communist Party for an anti-fascist "Popular Front". Shortly before it was dissolved its members established the Tribune magazine to support this campaign, which is still in existence to this day.