The origins of the group lie in the Spartacusbund, which existed until 1982. One faction in that organization still wanted establish a communist organization in West Germany and had contacts to the British group Workers' Power, so Arbeitermacht was founded. These two groups along with the French Pouvoir Ouvrier and the Irish Workers' Group founded the Movement for a Revolutionary Communist International. Soon they found supporters in Austria, Peru, and Bolivia, so the movement renamed itself to League for a Revolutionary Communist International and after adopting a new program in 2003 it got its present name League for the Fifth International (LFI).
The LFI's youth organization is REVOLUTION. After extended disputes about the role of the LFI in Revo, non-LFI members, who refer to themselves as "independents", formed a tendency called iRevo in the Summer of 2006. IRevo, which included a large part of the German section, were expelled in October 2006.