Cognomen Boudniak (Будняк 
, Boudniak 
) , across the world, is quite a rare last name. The family name Boudniak is characteristic of Ukraine, where it is quite a rare surname, Belarus, where it is a rare surname, and Kyrgyzstan. In absolute terms, this name is the most popular in Eastern Europe, particularly Ukraine, Russia, and Belarus.
| VARIANT | COUNTRY |
|---|---|
| Будняк | Kazakhstan, Russia, Kyrgyzstan, Belarus, Ukraine |
| Boudniak | Mexico, United States |