Peter M. Blau (1918–2002) was an American sociologist and theorist. Born in Vienna, Austria, he immigrated to the United States in 1939. He was an instructor at Wayne State University in Detroit, Michigan from 1949–1951, before moving on to teach at the University of Chicago from 1953 to 1970. In 1970 he returned to Columbia University, where he continued to teach until 1988. From 1988 to 2000 he taught as an emeritus professor at University of North Carolina, Chapel Hill.