Organizations affiliated with the International Socialist Tendency •
International Socialist Organization, an American Trotskyist group from 1976 to 2019 which was expelled from the International Socialist Tendency in 2001 •
International Socialists (Australia), an Australian Trotskyist group •
International Socialists (Brazil) •
International Socialists (Canada), a Canadian Trotskyist group formed in the 1970s •
International Socialists (Denmark), a Danish Trotskyist group formed in 1984 •
International Socialists (Ireland), a defunct Irish Trotskyist group •
International Socialists (Netherlands), a Dutch Trotskyist group formed in 1988 •
International Socialists (Norway), a Norwegian Trotskyist group from the 1980s to 2008 •
International Socialists (UK), now known as the Socialist Workers Party, a British Trotskyist group
Other Trotskyist organizations •
International Socialist Group, a British section of the reunified Fourth International from 1987 to 2009 • International Socialist Movement, a current within the Scottish Socialist Party from 2001 to 2006 •
International Socialists (Scotland), a Scottish organization affiliated with the
Committee for a Workers' International •
International Socialists (United States), an American organization from the 1960s to 1986
Other organizations •
International Socialist League, a South African communist party from 1915 to 1921 •
International Socialist Party, now known as the Communist Party of Argentina, an Argentinian communist party formed in 1918 •
International Socialists of Germany, a German left communist party in the 1910s == Other ==