Cognomen Gaidouk (Гайдук 
, Gaidouk 
) , worldwide, is a common last name. The family name Gaidouk is characteristic of Eastern Europe, particularly Belarus, where it is quite a common surname, Ukraine, and Russia, where it is quite a rare surname.
| VARIANT | COUNTRY |
|---|---|
| Гайдук | Kazakhstan, Russia, Kyrgyzstan, Belarus, Ukraine |
| Gaidouk | Germany, Italy, Canada, United States |