Cannibalism (from Caníbales, the Spanish name for the Carib people, a West Indies tribe formerly well known for their practice of cannibalism) is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy. A person who practices cannibalism is called a cannibal.

While the expression "cannibalism" has origins in the act of humans eating other humans, it has extended into zoology to mean the act of any animal consuming members of its own type or kind, including the consumption of mates.

A related word, "cannibalize" (from which "cannibalization" is derived), has several meanings which are metaphorically derived from cannibalism and originally referred to the reuse of military parts. In manufacturing, it can refer to reuse of salvageable parts. In marketing, it may refer to the loss of a product's market share to another product from the same company. In publishing, it can mean drawing on material from another source.

Cannibalism was widespread in the past among humans in many parts of the world, continuing into the 19th century in some isolated South Pacific cultures, and to the present day in parts of tropical Africa. In a few cases in insular Melanesia, indigenous flesh-markets existed. Fiji was once known as the 'Cannibal Isles'. Cannibalism has been well documented around the world, from Fiji to the Amazon Basin to the Congo to Māori New Zealand. Neanderthals are believed to have practiced cannibalism, and they may have been eaten by modern humans.