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