Moses ben Joseph ben Merwan ha-Levi (flourished about the middle of the twelfth century) was a prominent Provençal rabbi and Talmudist.
He was a nephew and pupil of Isaac ben Merwan ha-Levi. His colleagues addressed him as "Great scholar, Nasi Rabbi Moses," and his ritual decisions and Talmudic comments are often quoted.
He directed the yeshibah at Narbonne, several of his pupils subsequently achieving fame. Abraham ben David of Posquières and Zerahiah Gerondi were among his pupils. He was in continuous correspondence with his younger colleague Abraham ben Isaac, ab bet din, who was his pupil and who by preference sought Moses' advice in difficult casuistic questions.
Jacob ben Moses of Bagnols quotes a document relating to a divorce drawn up at Narbonne in 1134 and signed by the "great rabbi Moses ben Joseph and by Eliezer ben Zechariah." Gross identifies this Moses ben Joseph with Moses ben Joseph Merwan. If this identification is correct, Moses was one of the foremost cabalists of southern France, as Jacob's words in the passage cited indicate, although Moses is not otherwise known as a mystic.