Thesen is a surname. Notable people with the surname include:
Charles Wilhelm Thesen (1856–1940), Norwegian-born South African businessman Johan Thesen (1867–1945), Norwegian businessman Nils Peter Thesen (1853–1929), Norwegian-born South African businessman Rolv Thesen (1896–1966), Norwegian poet, literary researcher and literary critic Sharon Thesen (born 1946), Canadian poet