Last name รัตนายุ (รัตนายุ 
) , around the world, is an extremely rare cognomen. The family name รัตนายุ is habitual in South-eastern Asia, particularly Thailand, where it is an extremely rare surname. Much less frequently, รัตนายุ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| รัตนายุ | Thailand |