Abtei Mariendonk, Benedictine monastery in Grefrath, Germany.

Mariendonk Abbey is a Benedictine monastery near the Lower Rhine featuring a chapel, conference areas, and grounds with gardens and forest. The facility offers overnight accommodations and meals to visitors seeking to spend time on the premises.

The monastery was founded in 1900 when Mother Ursula Kleberg arrived with a group of sisters on donated land. The community was formally recognized as an abbey in 1948.

The monastery is shaped by the Benedictine nuns who follow a way of life rooted in prayer and community work. Visitors experience a daily rhythm centered on spiritual practice and reflection.

Guests stay in the guest wing completed in 1961, which also houses the library and the embroidery and weaving workshops. Since 1984 the guest chapel has let visitors join the nuns for Mass and the Liturgy of the Hours, celebrated in German. The abbey lies in Mülhausen, part of Grefrath near Kempen, close to the Niers lowland.

The name Mariendonk refers to the site itself: a Donk is a raised spot in marshland, here in the Niers floodplain. The abbey's library is a scientific library and member of the Arbeitsgemeinschaft Katholisch-Theologischer Bibliotheken. Since 1990 nuns have contributed to the bilingual Fontes christiani edition of the Church Fathers, and patristics courses for religious were set up in 1992.