This is a list of Trotskyist internationals. It includes all of the many political internationals which self-identify as Trotskyist.
Of the organizations listed, three claim to be the original Fourth International founded in 1938: the reunified Fourth International, the Fourth International (ICR), and the ICFI. 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. Some claim to represent a continuity from the Fourth International or to have re-established it: for example the Fourth International (ICR) International Centre/Center of Reconstruction, also known as the FI (La Verité), also calls itself the "Fourth International". Others argue that the title "Fourth International" is so discredited that a Fifth International or another new organisation is needed.
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.
There are also international groupings around some Trotskyist groups which have no formal international structure: