List of Trotskyist internationals

The Fourth International split into two factions 1953 over the question of historic perspective, with the International Secretariat (ISFI) turning in favour of deep entryism and supporting petty-bourgeois nationalist movements in less developed countries, and the International Committee (ICFI) upholding the need to form revolutionary parties.

The factions reunited in 1963 resulting in the formation of reunified Fourth International (USFI), while parts of the ICFI did not.

Both the USFI and ICFI went on to fragment further, giving rise to several new internationals.

Certain organizations which claim to be Trotskyist make no attempt to claim any relationship to the Fourth International in an organizational sense and argue that it no longer exists.

The various organizations listed here range in size from those having thousands of adherents in dozens of countries to tendencies which can barely claim a dozen members in three or four countries.