Marcellus II, né Marcellus Corvini (May 6, 1501 - May 6, 1555), cardinal of Santa Croce, a native of the area of Ancona, Italy, was elected pope to succeed Julius III on April 9, 1555, but his feeble constitution succumbed to the fatigues of the conclave, the exhausting ceremonies connected with his accession, and the anxieties arising from his high office, on the twenty-first day after his election. He had a high reputation for integrity, tact and ability. His successor was Paul IV

The Missa Papae Marcelli of Giovanni Pierluigi da Palestrina is traditionally connected with him.