Karlsen is a Danish-Norwegian patronymic surname meaning "son of Karl" (\k(a)-rl\), an Old German given name. The form Carlsen is cognate. The parallel Swedish forms are Karlsson and Carlsson. People with the surname include:

Alexandria Karlsen (born 1978), American model, actress and author Atle Karlsen (keyboardist) (?-), keyboardist of the Norwegian Rock band DumDum Boys Emil Karlsen (born 1997), Norwegian singer-songwriter Geir Karlsen (born 1948), Norwegian footballer Geir Karlsen (born 1965), Norwegian CEO Johan Sigurd Karlsen (1894–1967), Norwegian politician Kari Karlsen (born 1952), Norwegian high jumper Karl Henry Karlsen (1893–1979), Norwegian politician Morten Karlsen (born 1979), Danish footballer Svend Karlsen (born 1967), Norwegian strongman Tor Ottar Karlsen (born 1950), Norwegian politician

See also Styrmand Karlsen, a 1958 Danish film

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