The International Socialist League (ISL-LIS) is an international political organization made up of national revolutionary socialist and Trotskyist parties and organizations from five continents. The ISL was founded at a conference held in Barcelona on May 24 to 26, 2019. The initiative was a result of the merging of the organizations that made up the Anticapitalist Network - the Socialist Workers´ Movement (MST) of Argentina and Socialist Tide of Venezuela, among others - and the Socialist Laborers Party (SEP) of Turkey. The Anticapitalist Network was dissolved in a meeting the day before the ISL founding conference. Delegates from a score of countries founded the new international organization and voted on a common program at the Barcelona conference.