Peter Francis Flaherty (June 25, 1924 – April 18, 2005) was an American politician and attorney. He served as assistant district attorney of Allegheny County from 1957 to 1964, a member of the Pittsburgh City Council from 1966 to 1970, the 54th mayor of Pittsburgh from 1970 to 1977, United States deputy attorney general during the Carter administration from 1977 to 1978, and county commissioner of Allegheny County from 1984 to 1996.