Last name Kostyan (Костян 
, Kostyan 
, Костиан ) , around the world, is quite a rare family name. The last name Kostyan is habitual in Belarus, where it is quite a rare surname, Ukraine, where it is a rare surname, and Kazakhstan. Not in comparison with a country's population, the name is most common in Eastern Europe, particularly Belarus, Russia, and Ukraine. Much less frequently, Kostyan is the forename as well as the last name.