Joel Barnett, Baron Barnett, PC (born 14 October 1923), is a Labour member of the House of Lords. He was made a Life Peer in 1983.

He was formerly a Member of Parliament for Heywood and Royton, and served as Chief Secretary to the Treasury from 1974 to 1979 gaining a seat in the cabinet from 1977 onwards. During this time he oversaw the devising of what is known as the Barnett Formula by which Scotland and Wales receieve a higher proportion of government spending per head than England, due to the geographic problems of service provision.