Surname Seongjun (성준 
, Seongjun 
) , across the world, is a very rare family name. The cognomen Seongjun is habitual in Cambodia, where it is a very rare surname, China, where it is an extremely rare surname, and Malaysia. Measured by absolute frequency, it most frequently occurs in China, Cambodia, and the United States. Predominantly, Seongjun is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 성준 | South Korea |
| Seongjun | South Korea, China, Cambodia, Canada, United States |