Mithymna is a town and former municipality on the island of Lesbos, North Aegean, Greece. Since the 2019 local government reform it is part of the municipality of West Lesbos, of which it is a municipal unit. Before 1919, its official name was Μόλυβος - Molyvos; that name dates back to the end of the Byzantine Era, but is still in common use today.