Cognomen Остоя (Ostoja 
, Остоя 
) , globally, is a rare surname. The surname Остоя is characteristic of Croatia, where it is quite a rare surname, Poland, where it is a rare surname, and Argentina, where it is a very rare surname. Not in comparison with a country's population, it most frequently occurs in Poland, Croatia, and the United States. More prevalently, Остоя is the forename as well as the last name.