Cognomen Гулбай (Гулбай 
, Gulbai 
, Gulbaj ) , around the world, is a rare last name. The cognomen Гулбай is characteristic of Kyrgyzstan, where it is quite a rare surname, Turkey, where it is a rare surname, and Hungary, where it is a very rare surname. Not in comparison with a country's population, this name is the most popular in Kyrgyzstan, Turkey, and the United States. More prevalently, Гулбай is the forename as well as the last name.