A community of monks living by prayer and labour in secluded, often remote, locations. Such communities, which are meant to further the communal and individual practice of asceticism, are common to most religions. Buddha founded a monastic order (sangha) and a code of discipline, which is still used and was spread by missionaries throughout Asia. In Hinduism monasticism takes the form of ashrams, or retreats, where the influence of a guru or holy man and practices, such as yoga, are important. Islam did not fully develop a monastic organization until the Sufis formed the Rifaite and Mawlawite brotherhoods in the 12th century. Although monasticism is not part of mainstream Judaism, the Essenes, a messianic sect (2nd century bc) founded a remote community by the Dead Sea.

Christian monasticism evolved from the hermit communities founded in the 3rd century by men fleeing from Roman persecution to the Egyptian and Syrian deserts, where they sought union with God. Although St Antony (c.251–c.356) is usually regarded as the founder of Christian monasticism, it was St Pachomius (c.292–c.346) who founded the first organized community at Tabennisi in Egypt. Monasticism then spread rapidly in Eastern Europe through the Rule of St Basil (c.330–79), the first known Christian monastic rule, and in Western Europe through the Rule of Benedict of Nursia (c.480–c.550). In the Roman Catholic Church, however, there are numerous orders whose members are often bound by vows of poverty, prayer, and meditation. Communities have both spiritual and practical functions, such as education and social work. From the 10th century the reformed Benedictine Order at Cluny in France (founded 909) built a series of ‘daughter houses’ which extended throughout Europe, all under the direct control of the powerful abbot of Cluny. The Cistercians (founded 1098) also built monasteries in Europe and England, though these foundations enjoyed a semi-autonomous position and were only subject to the direct influence of the abbot of Citeaux at an annual council. The Cistercian Order follows the reformed Benedictine Rule; Cistercians of the Strict Observance (Trappist) form the largest contemplative order. Other orders were the Carthusians (1098), the Premonstratensians (1120), and the Gilbertines (1131). The Dominican Order, founded by St Dominic in 1220, and the Franciscan Order, founded by St Francis of Assisi in 1209, were originally mendicant orders of friars, living from charity, although now most of their members are based in community houses.

Monasticism in the Anglican Communion has become more prominent since the 19th-century Anglo-Catholic movement, with the re-foundation of some ancient orders and the establishment of new orders, such as the Community of the Resurrection, founded in 1892. The ecumenical Taizé community in France, founded in 1940, is the best-known Protestant order. Although Christian monasticism is declining in Europe, it is expanding in the developing world, where it plays an important role in providing educational and other welfare services.