Boniface I was pope from 418 to 422. He was a contemporary of Saint Augustine of Hippo, who dedicated to him some of his works.

On the death of Pope Zosimus, two parties put forward their own candidate for Pope, one for Boniface, the other for Eulalius. Galla Placidia asked the emperor Honorius to intervene, and he sent an edict instructing both men to leave Rome. At the following Easter, Eulalius returned to the city to perform baptisms and celebrate the feast; when the emperor heard of this, Eulalius was stripped of his rank and banished from Rome, and on December 28, 418 Boniface became Pope.

Boniface continued the opposition to Pelagianism, persuaded Emperor Theodosius II to return Illyricum to Western jurisdiction, and defended the rights of the Holy See. He died on September 4, 422.