Surname พจน์สมพงศ์ (พจน์สมพงศ์ 
) , around the globe, is an extremely rare last name. The family name พจน์สมพงศ์ is habitual in South-eastern Asia, particularly Thailand, where it is an extremely rare surname.
| VARIANT | COUNTRY |
|---|---|
| พจน์สมพงศ์ | Thailand |