The Canons Regular of San Giorgio in Alga were a congregation of canons regular which was influential in the reform movement of monastic life in northern Italy during the 15th and 16th centuries.
Its roots lay in the preaching of an itinerant canon regular, Bartolomeo of Rome, who was a proponent of the new spirituality of the Devotio Moderna which had developed in the Low Countries, and was starting to spread in northern Italy at that time. While ministering in Venice in 1396 he met two young noblemen, Gabriele Condulmer (the future Pope Eugene IV) and his cousin, Antonio Correr, the nephew of Cardinal Angelo Correr, soon elected as Pope Gregory XII. Under his inspiration, the cousins decided to give up their wealth and to lead lives of prayer and service. In 1400 they began to live together as a small religious community, modeled on the Brothers of the Common Life, following the Rule of St. Augustine. They lived in a house lent to them by a relative.
One of the first men to join them there was Lawrence Giustiniani, who was a deacon at the time, the first cleric of the small community. In 1404 they were given the use of a monastery of Augustinian friars on the isolated island of St. George in Alga, which was almost empty, by its commendatory prior, a young nobleman, Ludovico Barbo, who soon himself joined the community. The new monastery quickly grew to have 17 members, all members of the clergy by then, and received the approval of Pope Boniface IX on 30 November of that year.