The term Augustinians, named after Saint Augustine of Hippo (354–430), applies to two separate types of Catholic religious orders, and to some Anglican religious orders. Within Anglicanism the Rule of St Augustine is followed only by women, who form several different communities of Augustinian nuns. Within Roman Catholicism Augustinians may be members of either one of two separate and distinct types of Order:

• Several mendicant Orders of friars, who lived a mixed religious life of contemplation and apostolic ministry and follow the Rule of St. Augustine, a brief document providing guidelines for living in a religious community. The largest and most familiar, originally known as the Hermits of Saint Augustine (O.E.S.A. - Ordo Eremitarum sancti Augustini) and also as the Austin friars, is now simply referred to as the Order of Saint Augustine (O.S.A.). Two other Orders, the Augustinian Recollects and the Discalced Augustinians, were once part of the Augustinian Order under a single Prior General. The Recollect friars, founded in 1588 as a reform movement of the Augustinian friars in Spain, became autonomous in 1612 with their first Prior General, Enrique de la Sagrada. The Discalced friars became an independent religious congregation with their own Prior General in 1592, and were raised to the status of a separate mendicant Order in 1610.
• Various congregations of clerics, known as canons regular, who also follow the Rule of St. Augustine, and embrace the evangelical counsels and lead a semi-monastic life, while remaining committed to pastoral care, appropriate to their primary vocation as priests. They generally form one large community, which might serve parishes in the vicinity, and are organized into autonomous religious congregations, which normally are distinct by region.