Surname Dyby (Diep 
, Dieb 
, Dyby 
) , in the world, is a common family name. The cognomen Dyby is characteristic of British Virgin Islands, where it is quite a common surname, Macao, where it is quite a rare surname, and Vietnam. Not in comparison with a country's population, the name is most common in Vietnam, the United States, and Malaysia. Likewise, Dyby is the forename as well as the last name.