Yuhanna ibn Masawaih, also written Ibn Masawaih, Masawaiyh, and in Latin Mesue, Masuya, Mesue Major, Msuya, and Mesue the Elder, is a Syriac physician from the Academy of Gundishapur.
According to The Canon of Medicine for Avicenna and 'Uyun al-Anba for the medieval Arabic historian Ibn Abi Usaybi'a, Masawaiyh's father was Syrian and his mother was Slavic.