James Joseph Mallon (24 December 1874–12 April 1961), known as Jimmy Mallon, was a British economist and political activist.
Born in Chorlton near Manchester, Mallon became an apprentice jeweller and joined the Shop Assistants' Union. He studied at the Victoria University of Manchester, and also became very active in the Ancoats Settlement. In 1903, he joined the Independent Labour Party and the Fabian Society, and from 1905 he served a year on the executive of his union.
Mallon moved to London in 1906 to work at the Toynbee Hall settlement, and also became secretary of the National League to Establish a Minimum Wage. He also championed the Trade Boards Act, 1909, and subsequently became a member of thirteen trade boards.
During World War I, Mallon was appointed as Commissioner for Industrial Unrest, and following the war, he became Warden of Toynbee Hall, holding the post until 1954. He was also active in the Workers' Educational Association and Workers' Travel Association, and wrote extensively on economic matters for various newspapers and also pamphlets. He stood for Parliament as a Labour Party candidate at Saffron Walden in 1918 and Watford in 1922 and 1923, but was never elected.
In 1939, Mallon was made a Companion of Honour.