Cognomen Kyein (Kyein 
) , worldwide, is a rare last name. The family name Kyein is habitual in South-eastern Asia, particularly Myanmar, where it is quite a rare surname, Malaysia, where it is a very rare surname, and Thailand, where it is an extremely rare surname. Measured by absolute frequency, it is the most numerous in Myanmar, Malaysia, and China. More frequently, Kyein is the forename as well as the last name.