Cognomen Ivai (Ivai 
) , all around the world, is a rare surname. The cognomen Ivai is characteristic of Papua New Guinea, where it is quite a rare surname, Tanzania, where it is a very rare surname, and France. Not in comparison with a country's population, it is the most numerous in Papua New Guinea, India, and Tanzania. More frequently, Ivai is the forename as well as the last name.