Ruperto Donoso (November 10, 1914 - August 16, 2001) was a jockey in the sport of Thoroughbred horse racing best known for riding Phalanx to victory in the 1947 Belmont Stakes. He also rode Gilded Knight to a second-place finish in the 1939 Preakness Stakes. A native of Santiago, Chile, Donoso rode in Santiago and at the Hipódromo de Monterrico in Lima, Peru before moving to the United States and riding under contract to Alfred G. Vanderbilt's racing stable.