Kremsmünster Abbey (German: Stift Kremsmünster) is a Benedictine monastery in Kremsmünster in Upper Austria.
The monastery was founded in 777 by Tassilo III, Duke of Bavaria. According to the foundation legend, Tassilo founded the monastery on the site where his son, Gunther, had been attacked and killed by a wild boar during a hunting trip.
The first colony of monks came from Lower Bavaria, under Fateric, the first abbot. The new foundation received generous endowments from the founder and also from Charlemagne and his successors.
The position and reputation of the abbey soon became such that its abbots, in the absence of the bishop of the diocese (Passau), exercised the episcopal jurisdiction.
In the 10th century the abbey was destroyed in a raid by the Hungarians, and its possessions were divided among the Duke of Bavaria and other nobles and the bishops. It was restored, however, and recovered its property, under the emperor Henry II, when Saint Gotthard became abbot.
Kremsmünster, in common with other religious houses, then fell into a decline, which was fortunately halted by the action of bishop Altmann of Passau, who brought a community from Gottesau, and introduced the reformed observance of Cluny into the abbey. After this it became known as one of the most flourishing houses in Germany, "excelling all other abbeys" says an anonymous chronicler, "in observance and piety, also in respect to its lands, buildings, books, paintings, and other possessions, and in the number of its members prominent in learning and in art".
The monastic library was famous, and drew eminent scholars to Kremsmünster, where several important historical works were written, including histories of the bishops of Passau and of the dukes of Bavaria, and the chronicles of the abbey itself. Schrodl gives a list of writers connected with Kremsmünster from the eleventh to the 16th centuries, and of their literary labours. One of the most distinguished abbots was Ulrich Schoppenzaun (1454–1484), to whom, and to his disciple and successor Johann Schreiner (1505–1524), it is due that Kremsmünster survived the Reformation.