Cognomen อุปนิสัย (Upanisai 
, อุปนิสัย , Upanigkit ) , globally, is a very rare surname. The surname อุปนิสัย is characteristic of Thailand, where it is a very rare surname, and the United States, where it is an extremely rare surname. Much less frequently, อุปนิสัย is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Upanigkit, Upanisai, อุปนิสัย | Thailand |
| Upanant | United States, Thailand |