Libertarian League was a name used by two American libertarian or social anarchist organisations during the twentieth century.
The first Libertarian League was founded in Los Angeles in 1920. Although mainly anarchist its membership included people from many different political perspectives with the over-riding principle of "equal freedom" and liberty in all aspects of life. It mainly supported co-operative forms of socialism but small businesses. Reflecting the times it was particularly concerned with opposing prohibition and militarism. From 1922 to 1924 it published a journal called The Libertarian. The organisation was unable to maintain its broad coalition of different views and it broke up in the 1930s.
The second Libertarian League was founded in New York City in 1954 as a political organisation building on the Libertarian Book Club. Members included Sam Dolgoff, Russell Blackwell, Dave Van Ronk, Enrico Arrigoni, and Murray Bookchin. This league had a narrower political focus than the first, promoting anarchism and syndicalism. Its central principle, stated in its journal Views and Comments, was "equal freedom for all in a free socialist society". Branches of the League opened in a number of other American cities, including Detroit and San Francisco, but it lacked an organisational focus and never managed to establish a presence amongst other anarchist and syndicalist organisations. It was dissolved at the end of the 1960s.