Family name О'Брайан (O'Brian 
, O'Bryan 
, О'Брайан 
) , all over the world, is quite a rare last name. The last name О'Брайан is habitual in Saint Lucia, where it is quite a common surname, Australia, where it is quite a rare surname, and Ireland. In absolute terms, this name is the most popular in the United States, Australia, and Canada. Much less frequently, О'Брайан is the forename as well as the last name.