Kloster Marienberg, Burgenland, Cistercian monastery in Klostermarienberg, Mannersdorf an der Rabnitz, Austria

Kloster Marienberg is a Cistercian monastery in Klostermarienberg, built from 1680 on the ruins of the medieval abbey; it occupies the north wing and parts of the east wing of the founding complex. The plain two-storey building has simple Baroque rooms, some with ribbed vaults, and a cloister of which the north wing and half the east wing survive, with a Romanesque portal from around 1200. The former St George's Chapel was built into the east wing as a single-nave, four-bay room under a barrel vault.

The monastery was founded in 1197 as a daughter house of Stift Heiligenkreuz, beginning its long history in the region. Major reconstruction took place in 1680, and a new church was built in 1741, fundamentally reshaping the appearance of the complex.

The Hungarian name Borsmonostor is still used for the village and monastery. Since 1 September 2021, pastoral care of the Klostermarienberg parish has been carried out by monks of Stift Heiligenkreuz, who live in the monastery rooms; their superior is elected by the Heiligenkreuz abbot, appointed by the Lilienfeld abbot and installed as parish priest by the bishop of Eisenstadt.

The monastery is not open as a general museum; the European Dog Museum that occupied it closed in 2014. Since 1 September 2021, pastoral care of the Klostermarienberg parish has been carried out by monks of Stift Heiligenkreuz who live in the monastery rooms, so parts of the complex are in residential and parish use. The superior is chosen by the Heiligenkreuz abbot, appointed by the Lilienfeld abbot and installed as parish priest by the Eisenstadt bishop.

The European Dog Museum, open here until 2014, grew out of the collection of the cynologist Dieter Fleig. The monastery buildings also served as exhibition space. Since 1 September 2021, monks from Stift Heiligenkreuz have lived in the rooms again and serve the parish of Klostermarienberg.