Olsen or Ölsen may refer to:
Olsen Danish pronunciation: [ˈoːˀlsn̩] is a Danish-Norwegian patronymic surname meaning "son of Ole". The surname Olesen Danish pronunciation: [ˈoːləsn] has a similar origin. The Swedish parallel form is Olsson - "son of Ola". 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: