Family name Rusnjak (Русняк 
, Rusnjak 
) , across the world, is a rare cognomen. The surname Rusnjak is characteristic of Ukraine, where it is quite a rare surname, Slovenia, where it is a rare surname, and Croatia, where it is a very rare surname. Measured by absolute frequency, it most frequently occurs in Ukraine, Russia, and Germany.
| VARIANT | COUNTRY |
|---|---|
| Русняк | Ukraine, Russia, Kazakhstan |
| Rusnjak | Croatia, United States, Slovenia, Germany, Canada |