Surname Koii (Койи 
, Koii 
) , in all the world, is a very rare cognomen. The last name Koii is habitual in South-eastern Asia, particularly Malaysia, where it is a very rare surname, Thailand, where it is an extremely rare surname, and Philippines. Not in comparison with a country's population, it is the most numerous in India, the United States, and Malaysia. More prevalently, Koii is the forename as well as the last name.