A monastery is a building or complex of buildings that serves as the domestic quarters and workplaces of monastics, monks or nuns, whether living in communities or alone. Monasteries are religious institutions for men who wish to live a monastic life, while convents are comparable institutions that are meant for women. Monks and nuns who live in monasteries typically shun worldly goods to live a simple life of prayer and devotion.

Monasteries can be found in many different religions, including Christianity and Buddhism. In the Roman Catholic religion and to some extent in certain branches of Buddhism, there is a somewhat more specific definition of the term and many related terms. Buddhist monasteries are generally called vihara, while in Tibetan Buddhism, monasteries are often called gompa. In Cambodia, Laos, and Thailand, a monastery is called a wat, and in Burma, a monastery is called a kyaung.

In Christianity, a monastery may be an abbey (i.e., under the rule of an abbot), or a priory (under the rule of a prior), or conceivably a hermitage (the dwelling of a hermit). It may be a community of men (monks) or of women (nuns). A charterhouse is any monastery belonging to the Carthusian order. In Eastern Christianity, a very small monastic community can be called a skete, and a very large or important monastery can be given the dignity of a lavra.

Monasteries played an important role in medieval Europe, serving as institutions full of educators and scholars. Monks, with their skills in Latin and document-making, were frequently used by monarchs in their royal writing offices, or a monastery itself performed that function.