Zassenhaus is a German surname. Notable people with the surname include:
Hans Zassenhaus (1912–1991), German mathematician Zassenhaus algorithm Zassenhaus group Zassenhaus lemma Hiltgunt Zassenhaus (1916–2004), German philologist who aided Scandinavian prisoners during World War II, sister of Hans Zassenhaus
See also Brauerei Zassenhaus, a German brewery in Velbert (see :de:Brauerei Zassenhaus)