William Zebina Ripley (October 13, 1867 – August 16, 1941) was an American economist, lecturer at Columbia University, professor of economics at MIT, professor of political economy at Harvard University, and racial theorist.
Ripley was famous for his criticisms of American railroad economics and American business practices in the 1920s and 1930s and later for his tripartite racial theory of Europe.
His work of racial anthropology was later taken up by racial physical anthropologists, eugenicists, and white supremacists and was considered a valid academic work at the time, although today it is considered to be a prime example of scientific racism.