Euphrosyne Doukaina Kamaterina or better Kamatera (Greek: Εὐφροσύνη Δούκαινα Καματερίνα ἢ Καματηρά, c. 1155 – 1211) was a Byzantine Empress by marriage to the Byzantine Emperor Alexios III Angelos.
Euphrosyne was the daughter of Andronikos Kamateros, a high-ranking official who held the titles of megas droungarios and pansebastos and his wife, an unknown Kantakouzene. She was related to the Emperor Constantine X and Irene Doukaina, empress of Alexios I Komnenos. Both of her brothers had rebelled against Andronikos I Komnenos; one was imprisoned and the other was blinded.