The League for the Fifth International (L5I) is an international grouping of revolutionary Trotskyist organisations around a common programme and perspectives.

L5I was founded in 1989 as the Movement for a Revolutionary Communist International. Its first members groups were Workers' Power in Britain, the Irish Workers Group, and Gruppe Arbeitermacht (GAM) in Germany.

The League publishes a quarterly English-language journal entitled Fifth International. The majority of writers for this appear to be from the British group, although other sections publish journals in their own languages. Revolutionärer Marxismus is the German-language journal. The League previously published the journal Permanent Revolution, a more theoretical journal which looked at tactics that communist organisations use, theories of imperialism, and similar questions. This was followed by Trotskyist International which, although still theoretical, also looked more at current affairs.^{[citation needed]}

The L5I lists the following organisations as sections:

The L5I also has individual members in Ireland and Lebanon.^{[citation needed]}