Surname 성기 (성기 
, Sung-Ki 
, Seonggi 
) , worldwide, is an extremely rare cognomen. Much more prevalently, 성기 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| 성기 | South Korea |
| Sung-Ki | New Zealand, South Korea, United States |
| Seonggi | Canada, United States |
| Seong-Gi | United States |