The Greek Socialist League was a socialist organization in Greece. The Socialist Party of Greece had merged with the Democratic Party, forming the Democratic Party of Working People, in September 1953. The Socialist League was founded on December 6, 1953, as a platform for socialist politics inside the new party. The Socialist League did not consider itself as a political party as such, but rather an organized faction. The Socialist League published the journal Sosialistika fylla ("Socialist papers").
As of 1957, the Executive Committee of the Socialist League consisted of Dimitris Stratis (Chairman), Stratis Someritis (Vice-Chairman), Agnes Roussopoulos (General Secretary), Takis Kyrkos (Joint Secretary), D. Goutas, I. Sakellariou, I. Papatheodorou, E. Paraskevas, E. Anastassiadis, Katerina Athanassiadou, I. Laoutaris, T. Tzaveas, M. Anagnostaras, S. Issaris and G. Katsoulis.
The Socialist League became an observer to the Socialist International, at the 1955 congress of the International in London.