Antonio da Sangallo the Younger (or Antonio Cordiani) (April 12, 1484 - August 3, 1546) was a Florentine architect active during the Italian Renaissance. His grandfather Francesco Giamberti was a woodworker, and his uncles Giuliano da Sangallo and Antonio da Sangallo the Elder were noted architects of the time.

His work includes:

• Palazzo Baldassini
• Villa Madama in Rome (started 1518)
• St. Peter's Basilica in Rome (chief architect from 1520 on)
• Palazzo Farnese in Rome (1534-46), designed for Cardinal Alessandro Farnese