Manorialism, also known as seigneurialism, the manor system or manorial system, was the method of land ownership (or "tenure") in parts of Europe, notably France and later England, during the Middle Ages. Its defining features included a large, sometimes fortified manor house in which the lord of the manor and his dependents lived and administered a rural estate, and a population of labourers who worked the surrounding land to support themselves and the lord. These labourers fulfilled their obligations with labour time or in-kind produce at first, and later by cash payment as commercial activity increased. Manorialism was part of the feudal system.

Manorialism originated in the Roman villa system of the Late Roman Empire, and was widely practiced in medieval western Europe and parts of central Europe. An essential element of feudal society, manorialism was slowly replaced by the advent of a money-based market economy and new forms of agrarian contract.

In examining the origins of the monastic cloister, Walter Horn found that "as a manorial entity the Carolingian monastery ... differed little from the fabric of a feudal estate, save that the corporate community of men for whose sustenance this organisation was maintained consisted of monks who served God in chant and spent much of their time in reading and writing."

Manorialism faded away slowly and piecemeal, along with its most vivid feature in the landscape, the open field system. It outlasted serfdom in the sense that it continued with freehold labourers. As an economic system, it outlasted feudalism, according to Andrew Jones, because "it could maintain a warrior, but it could equally well maintain a capitalist landlord. It could be self-sufficient, yield produce for the market, or it could yield a money rent." The last feudal dues in France were abolished at the French Revolution. In parts of eastern Germany, the Rittergut manors of Junkers remained until World War II.