Last name Shlak (Shlak 
, Шлак 
) , throughout the world, is a rare surname. The surname Shlak is habitual in Libya, where it is quite a rare surname, Kazakhstan, where it is a rare surname, and Bulgaria. Not in comparison with a country's population, it is commonest in Libya, Russia, and Kazakhstan. Much less frequently, Shlak is the forename as well as the last name.