Idrieus (Ancient Greek: Ἱδριεύς Hidrieús; died 344 BCE) was a ruler of Caria, nominally the Persian Satrap, who enjoyed the status of king or dynast by virtue of the powerful position his predecessors of the House of Hecatomnus (the Hecatomnids) created when they succeeded the assassinated Persian Satrap Tissaphernes in the Carian satrapy.