Cognomen โรจนบุญธนา (โรจนบุญธนา 
) , all over the world, is an extremely rare family name. The cognomen โรจนบุญธนา is habitual in South-eastern Asia, particularly Thailand, where it is an extremely rare surname.
| VARIANT | COUNTRY |
|---|---|
| โรจนบุญธนา | Thailand |