Giacomo Lanfredini (26 Oct 1670 – 16 May 1741) was a Roman Catholic cardinal who served as Cardinal-Deacon of Santa Maria in Portico (1734–1741) and Bishop of Osimo e Cingoli (1734–1740).

[1][2] Giacomo Lanfredini was born to a noble family in Florence, Italy, the son of Costanza Sati.

[1] He was named as the first auditor of the Grand Duke of Tuscany but declined instead accepting a position as advocate.

[2] He was appointed successively as Relator of the Sacred Congregation of Good Government, Auditor of the Camerlengo of the Holy Roman Church, Canonist of the Apostolic Penitentiary (1728), Secretary of the Sacred Congregation of the Tridentine Council (1730), Canon of the patriarchal Vatican basilica (1730), Voter of the Supreme Tribunal of the Apostolic Signature (1731), Datary of the Apostolic Penitentiary (1733) and later regent.

[1][2] On April 4, 1734, he was consecrated bishop by Giovanni Antonio Guadagni, Cardinal-Priest of Santi Silvestro e Martino ai Monti and vicar general of Rome, assisted by Tommaso Cervini, Titular Latin Patriarch of Jerusalem, and Giuseppe Maria Feroni, Titular Archbishop of Damascus.