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, Belarus, Kyrgyzstan, Russia, Ukraine |
| Gaidouk | Canada, Germany, United States, Italy |