Giocondo, Or Jocundus, Fra Giovanni, an Italian architect, born in Verona about 1450, died in Rome about 1530. He was a Dominican friar, studied archaeology in Rome, and collected in that city upward of 2,000 ancient inscriptions, which he presented to Lorenzo de' Medici. He designed the fortifications of Treviso, saved the lagoons of Venice from inundation by diverting the waters to the sea near Chiog-gia, and in 1494-'8 was architect to the emperor Maximilian at Verona, where he built the palace of the council and the church of Sta, Maria della Scale. In 1500-'7 he was employed by Louis XII. in building the bridges (since restored) of Notre Dame and of the Hotel Dieu. He afterward constructed in Venice a great warehouse on the rialto, known as the Fondaco de' Tedeschi, for which Titian and Giorgione made decorations; but the greater part of it being destroyed by fire in 1514, he left Venice because the authorities, instead of permitting him to rebuild it in stone, ordered another structure of wood by an inferior architect. Bramante dying in the same year, Giocondo was appointed by the pope to succeed him as architect of St. Peter's, and labored on that grand edifice simultaneously with Raphael. He instructed Scaliger in Latin and Greek, and was proficient in philosophy, theology, and classical literature.

Having been the first to prepare a design of Julius Caesar's bridge across the Rhine, he wrote notes on the hitter's "Commentaries," which were issued in 1517 by Aldus Manutius the elder, who also published (1508-'14) Pliny's correspondence with Trajan, which Giocondo had discovered while in Paris.