Tommaso Riario Sforza (8 January 1782, Naples - 14 March 1857, Rome) was the Neapolitan Cardinal who, as protodeacon, announced at the end of the 1846 conclave the election of Cardinal Giovanni Mastai-Ferretti as Pope Pius IX. He was the son of Duke Nicola Riario Sforza and Princess Giovanna Di Somma. Cardinal Sisto Riario Sforza (1810-1877) was a nephew of his, and Cardinals Pietro Riario, O.F.M. (1445-1474), Raffaele Riario (1461-1521) and Alessandro Riario (1542-1585) were of the same family.