World Socialist Party of the USA
- Renounces violence, Soviet-style totalitarianism, money and all forms of leadership. They advocate a classless, "wageless, moneyless, free access society" without any national borders. Marxist but not Leninist.
- http://www.worldsocialism.org/usa/

Socialist Alternative
- Revolutionary Marxist organization, US section of the Committee for a Workers International (CWI). Formerly Labor Militant. Publishes "Justice" newspaper.
- http://www.socialistalternative.org

Workers World online
- Under the leadership of Sam Marcy, this group split from the Socialist Workers Party (US) in the late 1950s over the latter's condemnation of the Soviet invasion of Hungary. The website includes a news service and various writings by Marcy.
- http://www.workers.org/

International Socialist Organization
- Publishes the newspaper Socialist Worker and the magazine International Socialist Review.
- http://www.internationalsocialist.org