Euphrosyne Kastamonitissa (Greek: Εύφροσύνη Κασταμονίτισσα) was a Byzantine noblewoman of the Kastamonites family, a wife of Andronikos Doukas Angelos (a cousin of the ruling Komnenos dynasty) and mother of the two future Byzantine emperors from the Angelos family: Isaac II Angelos and Alexios III Angelos.