Napoleon A. Chagnon (born 1938) is an American anthropologist.

Born in Chagawa, Michigan , he studied the Yanomami people and has written many books on the subject, among others one especially successful called Yanomamo: The Fierce People.

In 2000, journalist Patrick Tierney wrote a controversial book called Darkness in El Dorado, in which he accused Chagnon of improper, unethical and criminal conduct. Most of the accusations were later debunked by a panel set up by the University of Michigan.