Last name เพชรแก้วกุล (เพชรแก้วกุล, Pethkaewkul 
) , in all the world, is a very rare cognomen. The cognomen เพชรแก้วกุล is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Pethkaewkul | Thailand |