The Club was a Trotskyist group in the United Kingdom. It operated inside the Labour Party and was the official section of the Fourth International from 1950 until 1953 when, after the FI split, it became part of the International Committee of the Fourth International. Led by Gerry Healy, it published the newspaper Socialist Outlook until this was banned by Labour, whereupon it began selling Tribune, and eventually began a new paper, The Newsletter. In 1959 it was reconstituted as the Socialist Labour League.

Most of Britain's later Trotskyist parties had their origins in The Club including the Militant tendency led by former Club member Ted Grant, the International Socialists and later the Socialist Workers Party led by Tony Cliff and Healy's Workers Revolutionary Party.

"The Club" was also the informal name used by Canadian Trotskyists led by Ross Dowson who were practicing entrism in the Co-operative Commonwealth Federation in the early 1950s. This group eventually became the League for Socialist Action.