Olsen (Danish pronunciation: [ˈoˀlsn̩]) is a Danish-Norwegian patronymic surname meaning "son of Ole".
The surname Olesen (pronounced [ˈoːləsn̩]) has a similar origin.
The Swedish parallel form is Olsson – "son of Ole".
Danish and Norwegian immigrants to English-speaking countries often changed the spelling to Olson in order to accommodate English orthographic rules.
Notable people with the surname include: