Cognomen Yoonja (Yoonja 
) , in all the world, is a very rare last name. The surname Yoonja is characteristic of Malaysia, where it is a very rare surname, and China, where it is an extremely rare surname. Likewise, Yoonja is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Yoonja | China, United States, Canada, Malaysia |