Mettlach abbey, Benedictine monastery in Mettlach, Germany.

Mettlach Abbey is a former Benedictine monastery in Mettlach, on the bank of the Saar River, made up of buildings from different centuries now used as the headquarters of Villeroy & Boch. The site brings together a Romanesque tower, a baroque chapel, and other stone structures arranged around a central courtyard.

The monastery was founded in the 7th century and changed hands several times over the following centuries before being dissolved during the French Revolution. In the early 19th century, the Boch family took over the site and converted it into a ceramics factory, which eventually became Villeroy & Boch.

The abbey's pilgrimage tradition began when Bishop Ruotbert of Trier (931–956) redirected a Pentecost procession from the southeast of the diocese to Mettlach. Around 990, Abbot Lioffin built St. Mary's Church as the burial church of founder Liutwin. The neo-Romanesque Lutwinus Chapel of 1892 stands where, by legend, an eagle shaded the sleeping Liutwin.

The outer grounds are freely accessible and the main structures can be seen from the outside without entering the company premises. A visit pairs well with a walk along the Saar, since the site sits right on the riverbank.

The Old Tower was built around 990, about 300 years after the monastery's founding, as a double chapel modelled on Charlemagne's octagonal palace chapel at Aachen; the founder Liutwin was buried in it. It is the oldest surviving building in Saarland.