Haraden Pratt (July 18, 1891 – August 1, 1969) was an American electrical engineer and radio pioneer.
He learned Morse code when young and worked briefly as a shipboard wireless operator before entering the University of California (Class of 1914).
In this role he installed radio equipment on Navy ships and maintained West Coast shore stations until 1918, when he moved to Washington, D.C., to take charge of the construction and maintenance of all high-power Navy radio stations.
When in 1926 the United States Congress passed the Air Commerce Act to fund radio aids to air navigation, J. Howard Dellinger of the National Bureau of Standards tapped Pratt and Harry Diamond to create a suitable radio beacon system in 1927–1928.
During World War II, Pratt served as Division Chief in the Office of Scientific Research and Development and was Chairman of the Radio Technical Planning Board 1945–1949, and in 1946 was an official observer of the Bikini atomic bomb tests.