Peter Michael Blau (February 7, 1918 – March 12, 2002) was an American sociologist and theorist. Born in Vienna, Austria, he immigrated to the United States in 1939. He received his PhD at Columbia University in 1952, and 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.