Last name О'Ніл (O'Neill 
, О'Ніл 
) , around the world, is a common family name. The cognomen О'Ніл is characteristic of Ireland, where it is a common surname, Jersey, and British Virgin Islands, where it is quite a common surname (explore the name in all countries). Not in comparison with a country's population, this name is the most popular in Ireland, the United States, and the United Kingdom.