'''Klaasen''' is Dutch patronymic surname ("son of Klaas"). Notable people with this name include:
* Arno Klaassen (born 1979), Dutch bobsledder * Davy Klaassen (born 1993), Dutch footballer * Jozef Klaassen (born 1983), Dutch rower *{{interlanguage link|Leo Klaassen|ja|L・H・クラーセン|nl|Leo H. Klaassen|pl||}} (1920–1992), Dutch economist * Mihkel Klaassen (1880–1952), Estonian Supreme Court judge *Nel Klaassen (1906–1989), Dutch sculptor * René Klaassen (born 1961), Dutch field hockey player * Fred Klaassen (born 1992), Dutch cricketer * Ryan Klaassen, lead plaintiff in the 2021 vaccine law case ''Klaassen v. Indiana University''
;Klaassens * Jan Klaassens (1931–1983), Dutch footballer
==See also== * Klaasen * Claassen * Klassen *{{interlanguage link|Jan Klaassen|nl|Jan Klaassen (pop)}}, the Dutch puppet version of Pulcinella (Mister Punch)
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Category:Dutch-language surnames Category:Patronymic surnames Category:Surnames derived from given names