Orchomenus or Orchomenos (Greek: Ὀρχομενός) was an ancient city of Arcadia, Greece, called by Thucydides (v. 61) the Arcadian Orchomenus (Ὀρχομενός ὁ Ἀρκαδικός), to distinguish it from the Boeotian town.
Originating as a prehistoric settlement, Orchomenus became one of the powerful cities in West Arcadia along with Tegea and Mantineia. The heyday of the city was between 7th–6th century BC and it became a rich city which minted its own currency.