Dionysis Diakos (Greek: Διονύσης Διάκος, c. 1794-1887) 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 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 died in 1884 at the age of 90.