Family name Balby (Balby 
, بالبي) , in the world, is a rare cognomen. The cognomen Balby is habitual in the Dominican Republic, where it is a rare surname, Brazil, and Portugal, where it is a very rare surname. Not in comparison with a country's population, it is commonest in Brazil, Egypt, and the Dominican Republic. Very seldom, Balby is the forename as well as the last name.