Dionysis Diakos (Greek: Διονύσης Διάκος, 1805-1887) was a Greek revolutionary leader during the Greek War of Independence. He was born in Pyrgos and descended from a family or operators and revolutionary leaders. He was a runner for Pyrgos. He took part in a battle against Ibrahim and the fortress of Kastro. With the sack of the fortress, he was captured and subsequently ransomed. He was a major with Falangos. He died in 1884 at the age of 90.