Family name Muoi (Muoi 
, Мыой) , across the world, is quite a rare cognomen. The cognomen Muoi is characteristic of South-eastern Asia, particularly Malaysia, where it is quite a rare surname, Vietnam, where it is a rare surname, and Singapore, where it is a very rare surname. In absolute terms, it most frequently occurs in Vietnam, Malaysia, and China. Likewise, Muoi is the forename as well as the last name.