Baccio D'Agnolo (born Bartolomeo Baglioni) (c. 1460-1543), was a Florentine woodcarver, sculptor and architect. He was known as Baccio (an abbreviation of Bartolommeo) and d'Agnolo (son of Angelo, his father's name). He started as a wood-carver, and between 1491 and 1502 did much of the decorative carving in the church of Santa Maria Novella and the Palazzo Vecchio in Florence. Having made his reputation as a sculptor he appears to have turned his attention to architecture, and to have studied at Rome, though at what precise date is uncertain; but at the beginning of the 16th century he was engaged with Simon Pollajuolo in restoring the Palazzo Vecchio, and in 1506 he was commissioned to complete the drum of the cupola of the metropolitan church of Santa Maria del Fiore. The latter work, however, was interrupted on account of adverse criticisms from Michelangelo, and it remained unexecuted.

Baccio d'Agnolo also planned the Villa Borghese and the Bartolini palace, with other fine palaces and villas. The Bartolini palace was the first house to be given frontispieces of columns to the door and windows, previously confined to churches; he was ridiculed by the Florentines for his innovation. Another much-admired work of his was the campanile of the church of Santo Spirito . His studio was the resort of the most celebrated artists of the day, Michelangelo, Sansovino , the brothers Antonio da Sangallo the Elder and Giuliano da Sangallo and the young Raphael. He died in 1543, leaving three sons, all architects, the best-known being Giuliano D'Agnolo .

Giorgio Vasari included Baccio in volume IV of his Vite.