Baldassarre Peruzzi (7 March 1481 - 6 January 1536) was an Italian architect and painter, born in a small town near Siena and died in Rome. He worked for many years, beginning in 1520, under Bramante, Raphael, and later Sangallo during the erection of the new St. Peter's. He returned to his native Siena after the Sack of Rome (1527) where he was employed as architect to the Republic. For the Sienese he built new fortifications for the city and designed (though did not build) a remarkable dam on the Bruna River near Giuncarico. He seems to have moved back to Rome by 1535.
He was a painter of frescoes in the Cappella San Giovanni in the Duomo of Siena.
His son Giovanni Sallustio was also an architect.