Giovanni Antonio Serbelloni (Gian Antonio, Gianantonio) (1519-1591) was an Italian Cardinal, created in 1560, and papal legate. He was a cousin of Pope Pius IV, or nephew or uncle. He was bishop of Foligno in 1557 and bishop of Novara in 1560. He was bishop of Sabina and then bishop of Palestrina in 1573, bishop of Frascati in 1583, bishop of Ostia in 1589. He died in Rome in 1591 and was buried in Santa Maria degli Angeli e dei Martiri.