Surname Mastylo (Mastylo 
, Мастыло 
) , in the entire world, is a very rare last name. The last name Mastylo is characteristic of Kazakhstan, where it is a very rare surname, Russia, and Ukraine, where it is an extremely rare surname. In absolute terms, the name is most common in Russia, Kazakhstan, and the United States. Likewise, Mastylo is the forename as well as the last name.