Family name Koshliak (Koshliak 
, Кошляк 
) , in the entire world, is quite a rare surname. The surname Koshliak is habitual in Ukraine, where it is quite a rare surname, Kazakhstan, where it is a rare surname, and Russia.
| VARIANT | COUNTRY |
|---|---|
| Koshliak | Ukraine, United States |
| Кошляк | Kazakhstan, Russia, Kyrgyzstan, Belarus, Ukraine |