Marienfeld Abbey, Cistercian monastery in Harsewinkel, Germany.

Marienfeld Abbey is a Cistercian monastery in Harsewinkel, North Rhine-Westphalia, featuring a main church, stone walls, and garden grounds laid out across its property. The complex preserves functional spaces designed for religious life and communal activities typical of medieval monastic settlements.

Founded on 1 November 1185 by twelve monks from Hardehausen, the abbey was named Campus Sanctae Mariae. The abbey church was consecrated on 4 November 1222 by Dietrich III von Isenberg, Prince-Bishop of Münster. The Reichsdeputationshauptschluss of 1803 dissolved the abbey after 618 years; the last abbot, Petrus von Hatzfeld, received 5,000 florins and the 27 remaining monks 600 each.

The abbey's name reflects medieval devotion to Mary, and its architecture embodies Cistercian values of simplicity and functionality over ornament.

The church is owned by the state of North Rhine-Westphalia and used as a parish church under a 1804 foundation. Parts of the former economic buildings also belong to the state and house the priest, sacristan and organist; other buildings are privately owned and used as flats or for a hotel. A piece of masonry from the old Wadenhart chapel is visible on the north side of the gatehouse.

At the dissolution in 1803 the abbey held about 600 acres of land, 400 dependent properties and 100,000 Reichstaler in cash, plus a library of 7,000 volumes and 320 paintings. The last abbot, Petrus von Hatzfeld, received 5,000 florins; each of the remaining 27 monks got 600.