Cognomen ถนอมวงศ์ (ถนอมวงศ์ 
, Thanomwong 
) , across the world, is a rare last name. The last name ถนอมวงศ์ is habitual in Thailand, where it is quite a rare surname, Norway, where it is a very rare surname, and the United States, where it is an extremely rare surname. Also, ถนอมวงศ์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| ถนอมวงศ์ | Thailand |
| Thanomwong | Norway, United States, Thailand |