Surname พจน์สิทธิ์ (พจน์สิทธิ์ 
) , all over the world, is an extremely rare cognomen. The last name พจน์สิทธิ์ is habitual in South-eastern Asia, particularly Thailand, where it is an extremely rare surname. Also, พจน์สิทธิ์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| พจน์สิทธิ์ | Thailand |