Family name Osap (Osap 
) , in all the world, is a very rare surname. The last name Osap is habitual in Croatia, where it is a rare surname, Thailand, where it is an extremely rare surname, and the United States. Not in comparison with a country's population, it is the most numerous in the United States, India, and Croatia. More prevalently, Osap is the forename as well as the last name.