Frederick William Mulley, Baron Mulley of Manor Park in the City of Sheffield, PC, (born July 3, 1918) was a British Labour politician, barrister-at-law, and economist.

He served in the Worcestershire Regiment in the Second World War, but was captured in 1940 and spent five years as a prisoner of war in Germany. During this time he obtained a BSc in Economics and became a Chartered Secretary.

At the end of the war, he received an Adult Scholarship to Christ Church College, Oxford, and after a brief spell on an economics fellowship at the University of Cambridge (1948-50) he trained as a barrister, being called to the Bar in 1954.

A member of the Labour Party since 1936, he unsuccessfully contested the constituency of Sutton Coldfield in 1945, and became Member of Parliament for Sheffield, Park in 1950, a position he held until retiring at the 1983 General Election.

During a long career in politics he held a variety of ministerial positions including Minister of Aviation (1965-7), Minister for Disarmament (1967-9), and Minister of Transport (1969-70, 1974-5). In 1975 Harold Wilson brought him to the Cabinet as Secretary of State for Education and Science, and in 1976 became Secretary of State for Defence.

After retiring from the House of Commons in 1983, he was awarded a life peerage in 1984 and held a variety of directorial positions.