Family name Harnnarujchai (Harnnarujchai 
) , in all the world, is an extremely rare last name. The family name Harnnarujchai is habitual in South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Harnnarujchai | Thailand |
Natthadech, and Nattapong