Lassen is a Danish and Norwegian patronymic surname meaning "son of Lars" (equivalent of Laurentius), and thus a parallel form of the more common surname Larsen. Notable people with the surname include:
Anders Lassen (1920–1945), Danish recipient of the British Victoria Cross Christian Lassen (1800-1876), Norwegian-German orientalist Christian Riese Lassen, American artist known for marine art Clyde Everett Lassen, United States Navy aviator and Medal of Honor recipient Eduard Lassen, Belgian composer Erik Sætter-Lassen (1892–1966), Danish sport shooter
Georg Lassen, German U-boat captain Hartvig Lassen (1824–1897), Norwegian editor and literary historian Henrik Andreas Zetlitz Lassen, Norwegian politician Inger Lassen (1911–1957), Danish actress Jean Elisabeth Lassen, Canadian weightlifter Justin Lassen, American composer, producer, multi-instrumentalist and remixer Leigh Lassen, American actress Leo Lassen (1899–1975), American baseball announcer Niels A. Lassen (1926–1997), Danish medical researcher Peter Lassen, Danish-American rancher, prospector and explorer Peter Lassen (footballer), Danish football player Werner Lassen, Namibian golfer
Lassen may also refer to Lassen Peak, located in Lassen Volcanic National Park, a national park in the United States.
See also Larsen (disambiguation) Larson (disambiguation)