Gaddi, Taddeo (1300?-1366?), Florentine painter and architect, the most important of the pupils of the Florentine painter Giotto, assisting his master for 24 years, as well as painting independently. After Giotto's death Gaddi became the leading painter of the Florentine school for several decades.

Taddeo dutifully followed Giotto's principles in his work, setting his naturalistic figures against somber landscapes. He also experimented with the depiction of individualized human features and with lighting effects, both in his altarpieces and in his numerous frescoes.

Among Taddeo's frescoes are the series illustrating the life of the Virgin (1338?, Baroncelli Chapel, Santa Croce, Florence); Last Supper and Tree of Life (both 1340?, Refectory of Santa Croce); and frescoes in the Church of San Francesco, Pisa.

Among his altarpieces are Virgin in Glory (1355, Uffizi, Florence), and Madonna and Child Enthroned, with Saints (Metropolitan Museum of Art, New York City). His architectural career, according to the Italian biographer Giorgio Vasari, included the building of the Ponte Vecchio over the Arno River in Florence, and the continuation of work on Giotto's Campanile of Florence Cathedral. His son Agnolo Gaddi studied under him and later worked in Florence, Rome, and Prato.