René Wellek (August 22, 1903 – November 11, 1995) was a Czech-American comparative literary critic. Like Erich Auerbach, Wellek was an eminent product of the Central European philological tradition and was known as a vastly erudite and "fair-minded critic of critics."

René Wellek was born and raised in Vienna, speaking Czech and German. He studied literature at the Charles University in Prague, and was active among the Prague School linguists there, before moving to teach at London's School of Slavonic and East European Studies in 1935; the School is now part of UCL. His younger brother Albert Wellek (1904-1972) was one of the founders of musical psychology and lived in Germany. Before 1939, Wellek published some 60 items, all written in Czech.

From 1939, the beginning of World War II in Europe, Wellek lived in America. He taught first at the University of Iowa for seven years until 1946, and then, beginning in that year, at Yale University, where he established and chaired a department of comparative literature. In the United States, he was "widely regarded as a founder of the study of comparative literature." With Austin Warren, Wellek published a landmark volume entitled Theory of Literature, one of the first works to systematize literary theory.