Steven Izenour (July 16, 1940 in New Haven – August 21, 2001 in Vermont) was an American architect, urbanist and theorist. He is best known as co-author, with Robert Venturi and Denise Scott Brown, of Learning from Las Vegas, one of the most influential architectural theory books of the twentieth century. He was also a principal in the Philadelphia firm Venturi, Scott Brown & Associates.
He was born in New Haven, Connecticut, where his father George Izenour, a theatre stage and lighting designer, taught at Yale University and later had a consulting firm. His mother was Hildegard Hilt. In 1964, Izenour married Elisabeth Margit Gemmill.