Moses Hagiz (1671 – c. 1750) (Hebrew: משה חגיז) was a Talmudic scholar, rabbi and writer born in Jerusalem during the time of the Old Yishuv.

Returning to Jerusalem, he was given letters of recommendation nominating him as a rabbinical emissary or shadar sent to obtain support for a bet ha-midrash (study hall) which he intended to establish.

Arriving at Livorno, he secured from Vega, the protector of his family, a promise of further support; but his Palestinian enemies slandered him and ruined his prospects.

In Amsterdam he made the acquaintance of Tzvi Ashkenazi, then rabbi of the Ashkenazic congregation, and assisted him in unmasking the impostor Nehemiah Hayyun.

When Hagiz came to Amsterdam he immediately became embroiled in disputes with the Sephardic lay leadership, criticizing their lax religious observance and their anti-Rabbinic attitudes.

When Nehemiah Hayyun arrived in Amsterdam and the Sephardic community agreed to publish his books, Hagiz, with the help of Hakham Tzvi Ashkenazi, began a crusade against his apparent Sabbateanism.

Hagiz was instrumental in the Eastern European anti-Sabbatean campaigns of the 1720s and 1730s, writing letters and books against Sabbatean thinking, and rallying the support of communities throughout the Jewish world.

[3] Rabbi Yeshayahu Basan the mentor and staunchest defender of Luzzato describes Hagiz in one letter as a person who loves to quarrel and eager to criticize people's works, and that in one instance he criticized an author in regards to a claim that turned out to be an old Jewish tradition predating the author many hundreds of years.

(Among Sephardic Jews the Nun (letter) was used in its ending form to represent the Arabic word "ibn", meaning son of)