Poljak is a surname. Notable people with the surname include:
Allegra Poljak (born 1999), Serbian professional footballer Eszter Poljak (born 1952), Yugoslav sports shooter Maja Poljak (born 1983), Croatian volleyball player Mateo Poljak (born 1989), Croatian professional footballer Miroslav Poljak (1944–2015), Croatian water polo player Roberto Poljak (1932–2019), Argentine biophysicist and immunologist Stjepan Poljak (born 1983), Croatian football midfielder Željko Poljak (born 1959), Croatian basketball coach