John Ernest of Hanau-Münzenberg-Schwarzenfels (13 June 1613 in Schwarzenfels – 12 January 1642 in Hanau) was the last Count of the Hanau-Münzenberg line. He succeeded his grand-nephew Philip Louis III in 1641. When John Ernest died in 1642 Hanau-Münzenberg fell to the Hanau-Lichtenberg line.