Baldassare Tommaso Peruzzi (March 7, 1481 – January 6, 1536) is an Italian architect and painter, born in a small town near Siena (in Ancaiano, frazione of Sovicille) and dies in Rome.

He works for many years with Bramante, Raphael, and later Sangallo during the erection of the new St. Peter's.

He returns to his native Siena after the Sack of Rome (1527) where he is employed as architect to the Republic.

For the Sienese he builds new fortifications for the city and designs (though does not build) a remarkable dam on the Bruna River near Giuncarico.

He seems to have moved back to Rome permanently by 1535.

He is a painter of frescoes in the Cappella San Giovanni (Chapel of St. John the Baptist) in the Duomo of Siena.

His son Giovanni Sallustio is also an architect.