Giacomo Filippo Fransoni (born 10 December 1775, died 20 April 1856) was an Italian Cardinal who served from 1834 to 1856 as Prefect of the Sacred Congregation for the Propagation of the Faith.
Born in Genoa, he was ordained a priest on 14 March 1807, at 31 years of age, by Cardinal Pietro Francesco Galeffi.
On 7 September 1822 he was appointed Titular Archbishop of Nazianzus and ordained to the episcopate three months later. On 21 January 1823, aged 47, he was appointed Apostolic Nuncio to Portugal. On 2 October 1826, aged 50, he was elevated to the cardinalate and named Cardinal-Priest of Santa Maria in Ara Coeli.
On 21 November 1834, he was appointed Prefect of the Sacred Congregation for the Propagation of the Faith in the Curia. On 28 September 1855, aged almost 80, his titular church was changed to that of San Lorenzo in Lucina.
He died on 20 April 1856, aged 80. He had been a priest for 49 years, a bishop for 33 and a cardinal for almost 30.
Cardinal Fransoni is in the episcopal lineage of Pope Benedict XVI.