Nong Nam Sai (หนองน้ำใส) is a sub-district, (Tambon), in the Sikhio District of Nakhon Ratchasima Province, Thailand. It was created in 1996, and covers 101 km, 18 villages, and 12,443 citizens.

14°55′33″N 101°29′03″E / 14.925762°N 101.484083°E / 14.925762; 101.484083