Surname คอย (Khoi 
, คอย 
) , worldwide, is quite a rare family name. The last name คอย is habitual in Malaysia, where it is quite a rare surname, Vietnam, and Taiwan, where it is a rare surname. Measured by absolute frequency, this name is the most popular in South-eastern Asia, particularly Vietnam, Malaysia, and Indonesia. More prevalently, คอย is the forename as well as the last name.