Marcello Santacroce (7 June 1619 – 19 December 1674) was a Roman Catholic cardinal who served as Bishop of Tivoli (1652–1674).

[1] He studied theology, Greek, and Latin before earning his doctorate in law in Rome.

[1] On 14 August 1639, he was appointed Canon of the Vatican and later the Referendary of the Tribunals of the Apostolic Signature of Justice and of Grace; Prelate of the Sacred College of Good Government; Commissary to bring the peace among the people of Rieti; Vice-legate of Bologna; and the Commissary general of the three legations, Bologna, Ravenna and Ferrara.

[1] On 19 February 1652, he was elevated to Cardinal by Pope Innocent X in the Consistory of 1652 and on 12 March 1652, he was installed with the title of Cardinal-Priest of Santo Stefano al Monte Celio.

[1] On 28 October 1652, he was consecrated bishop by Fabio Chigi, Cardinal-Priest of Santa Maria del Popolo, with Giambattista Spada, Titular Patriarch of Constantinople, and Ranuccio Scotti Douglas, Bishop Emeritus of Borgo San Donnino, serving as co-consecrators.