Klassen is a surname. Notable people with the surname include:
Ben Klassen (1918–1993), American white supremacist and founder of the religion CreativityCindy Klassen (born 1979), Canadian skaterDanny Klassen (born 1975), American-Canadian baseball playerJohann Peter Klassen (1889–1947), German-Canadian poetKenneth Klassen (born 1951), Canadian sex touristKim Klassen (born 1968), American folk art painterLinda Klassen, Canadian politicianPeter P. Klassen (born 1926), Paraguayan Mennonite historianSarah Klassen (born 1932), Canadian poetTerry Klassen, Canadian voice actor and voice director