Last name Klej (Klej 
, Клей 
, קליי 
) , all over the world, is a rare cognomen. The family name Klej is habitual in Poland, where it is a rare surname, Ukraine, and Israel, where it is a very rare surname. Not in comparison with a country's population, it most frequently occurs in Eastern Europe, particularly Poland, Ukraine, and Russia. More frequently, Klej is the forename as well as the last name.