Cognomen Sieńkowski (Sieńkowski 
) , across the world, is a rare surname. The family name Sieńkowski is habitual in Eastern Europe, particularly Poland, where it is a rare surname.
| VARIANT | COUNTRY |
|---|---|
| Sieńkowski | Poland |
| maciej sieńkowski Polish painter (1962-2014), PL (b. 1962) |
|