Oscar Lewis, born Lefkowitz (December 25, 1914 – December 16, 1970) was an American anthropologist. He is best known for his vivid depictions of the lives of slum dwellers and his argument that a cross-generational culture of poverty transcends national boundaries. Lewis contended that the cultural similarities occurred because they were "common adaptations to common problems" and that "the culture of poverty is both an adaptation and a reaction of the poor classes to their marginal position in a class-stratified, highly individualistic, capitalistic society." He won the 1967 U.S. National Book Award in Science, Philosophy and Religion for La Vida; A Puerto Rican Family in the Culture of Poverty.
Lewis was the son of a rabbi, born 1914 in New York City and raised on a small farm in upstate New York. He received a bachelor's degree in history in 1936 from City College of New York, where he met his future wife and research associate, Ruth Maslow. As a graduate student at Columbia University, he became dissatisfied with the History Department at Columbia. At the suggestion of his brother-in-law, Abraham Maslow, Lewis had a conversation with Ruth Benedict of the Anthropology Department. He switched departments and then received a Ph.D. in anthropology from Columbia in 1940. His Ph.D. dissertation on the effects of contact with white people on the Blackfeet Indians was published in 1942.
Lewis taught at Brooklyn College, and Washington University, and helped to found the anthropology department at the University of Illinois Urbana-Champaign. He died in New York City of heart failure, at age 55 in 1970, and was buried in Montefiore Cemetery in Springfield Gardens, Queens.