Nicolaos Matussis, also spelled as Nicolae Matussi[1] (Greek: Νικόλαος Ματούσης; 1899–1991), was an Aromanian lawyer, politician and leader of the Roman Legion, a collaborationist, separatist Aromanian paramilitary unit active during World War II in central Greece.

Together they founded the Aromanian separatist state of the Principality of the Pindus, spanning from Thessaly to Epirus and Macedonia, and encompassing all Aromanian-populated areas within Greece.

Matussis, Demosthenes Tsoutras and Konstantinos Tahas confounded the Italian-sponsored Roman Legion which became the state's official military force.

[2] Following King Michael's Coup, the Romanian Communist Party seized power in the country, sentencing Matussis to 20 years in prison on a Danube island.

In this court (which took place in Athens, far from Larissa where he was active) and with the support of defense witnesses he was declared innocent of war crimes.