Mastichochoria (, , lit. "the mastic villages" in English) is a former municipality on the island of Chios, North Aegean, Greece. Since the 2011 local government reform it is part of the municipality Chios, of which it is a municipal unit. It is located in the southwestern and extreme southern part of the island. It is the largest municipal unit in land area on Chios at 211.687 km2. Its population was 3,672 at the 2001 census. The seat of the municipality was Pyrgi (pop. 755). The next largest villages are Kalamotí (569), Armólia (442), Mestá (337), and Lithío (397). The small coastal village of Emporeios (47) boasts an archaeological site.