Gregory Kamateros (Greek: Γρηγόριος Καματηρός, romanized: Grēgorios Kamatēros; fl. 1088 – c. 1126/32) was a senior Byzantine official. Of low birth but very well educated, he reached high office under Emperor Alexios I Komnenos and eventually became logothetes ton sekreton, de facto prime minister, under both Alexios and John II Komnenos. Through his marriage with Irene Doukaina, an imperial relative, he founded the bureaucratic dynasty of the Doukai–Kamateroi.