Althoff is a surname. Notable people with the surname include:
Althoff (Circus), one of the oldest and greatest Circusfamilies in the world, existing since 1660Ernie Althoff, an Australian musicianFriedrich Althoff (1839–1908), Prussian Minister of Culture, Honorary degree from Harvard,…Adolf & Maria Althoff, Owner of a German Althoff-Circus, Righteous Among the NationsKai Althoff (born 1966), German painterPamela Althoff (born 1953), a Republican Illinois State SenatorWilliam Althoff, principal of St. Vincent's High School in 1883