Klassen is a surname. Notable people with the surname include:
Ben Klassen (1918–1993), American white supremacist and founder of the religion Creativity Cindy Klassen (born 1979), Canadian skater Heinrich Klassen (born 1991), South African cricketer Danny Klassen (born 1975), American-Canadian baseball player Eduard Klassen, Paraguayan harpist Ernie Klassen, Canadian politician George Klassen (born 2002), American baseball player Johann Peter Klassen (1889–1947), German-Canadian poet Jon Klassen (born 1981), Canadian writer and illustrator of children's books Kenneth Klassen (born 1951), Canadian sex tourist Linda Klassen, Canadian politician Owen Klassen (born 1991), Canadian basketball player Peter P. Klassen (1926–2018), Paraguayan Mennonite historian Sarah Klassen (born 1932), Canadian poet Terry Klassen, Canadian voice actor and voice director
See also Classen (surname) Kelasen, a village in Sarawak, Malaysia, whose alternative name is Klassen Klaassen