Tegernsee Abbey, Benedictine abbey in Tegernsee, Germany

Tegernsee Abbey is a former Benedictine monastery whose buildings now form Schloss Tegernsee, a large cream-coloured complex with a long red-tiled roof, two square towers with grey spires and clock faces, and a central stone entrance with an arched doorway and circular window. The site also includes the parish church of St. Quirinus, the Tegernsee Grammar School and the Bräustüberl brew pub.

The monastery was founded around 760–765 by the brothers Otkar and Adalbert of the Huosi clan, according to a legend recorded in the Passio Sancti Quirini. After the fall of Duke Tassilo III it became a Carolingian royal monastery, declined in the 10th century, and was re-founded as an imperial abbey in 978 under Otto II. Under Abbot Ellinger and the monk Froumund it became a centre of manuscript production, and its foundry cast the Mainz cathedral doors in 1014.

The name Tegernsee comes from the Old High German tegarin seo, "great lake". Monks here copied manuscripts and wrote works such as the Ruodlieb and the Play of the Antichrist, and Abbot Gozbert founded a bell foundry in 1083. Today the former monastic buildings hold the Bräustüberl of the Tegernsee brewery, a ducal Bavarian brewery pub and restaurant.

The former abbey buildings stand in the town centre of Tegernsee, a short walk from the lake shore. The Bräustüberl of the Tegernsee brewery and a restaurant occupy part of the premises, and the Gymnasium Tegernsee uses other rooms; the parish church of St. Quirinus, the former abbey church, is open to visitors. The ducal private quarters are not accessible.

The abbey's scriptorium produced the Ruodlieb, a Latin verse epic written around 1050 by a Tegernsee monk, and the Play of the Antichrist, a Latin liturgical drama from the same era. Around 1500 the librarian Konrad Sartori compiled the Liber illuministarum there, a collection of over 750 recipes for parchment, pigments and gilding.