A hippopotamus is a large, mostly herbivorous African mammal.

Hippopotamus may also refer to:

• Hippopotamus (album), a 2017 album by Sparks
• Hippopotamus (genus)
• Hippopotamus (hieroglyph), an Egyptian hieroglyph
• Hippopotamus (restaurant), a French chain of grill restaurants
• The Hippopotamus, a 1994 novel by Stephen Fry
  • The Hippopotamus (film), a 2017 film adaptation of the novel
• Hippopotamus Defence, an opening strategy in chess

• Hippo (disambiguation)
• Cyprus dwarf hippopotamus, an extinct species
• Hippopotamus antiquus or "European hippopotamus", an extinct species
• Hippopotamus creutzburgi, an extinct species
• Hippopotamus gorgops, an extinct species
• Hippopotamus melitensis or "Maltese hippopotamus", an extinct species
• Hippopotamus pentlandi or "Sicilian hippopotamus", an extinct species
• Malagasy hippopotamus, several extinct species
• Pygmy hippopotamus, a related species
• William the Hippopotamus, an Egyptian faience hippopotamus statuette from the Middle Kingdom