Weihenstephan Abbey (Kloster Weihenstephan) was a Benedictine monastery in Weihenstephan, now part of the district of Freising, in Bavaria, Germany. Brauerei Weihenstephan, located at the monastery site since at least 1040, is said to be the world's oldest continuously operating brewery.
Saint Korbinian, whose arrival in Freising is dated at around 720, founded a church dedicated to Saint Stephen here. A dormitory for monks that originally adjoined the building disappears from records by the end of the eighth century. The monastery itself, dedicated at first to Saint Vitus, then later to Saints Stephen and Michael, was founded by Bishop Hitto von Freising between 811 and 835. From then until 1020 or 1021 it was a monastery of Augustinian canons before becoming a Benedictine abbey.
The abbey was dissolved in 1803 during the secularisation of Bavaria and its property sold off. In 1810 the abbey church, which had been made into a parish church, was demolished.
In 1803 the Forestry School of Munich was moved into the empty buildings; at the same time a model farm was established. A large part of the previous abbey economy, with buildings and stables as well as forests and fields, was transferred to the forestry school or the model farm. From 1804 agricultural science was taught here by Max Schönleutner.
As early as 1807 both schools were wound up, as many teachers and students had taken part in Napoleon's invasion of Russia, from which few had returned. In 1852 the agricultural school was re-established in Weihenstephan and in 1895 became an agricultural college, which formed the nucleus of the Technical University of Munich life sciences campus in Freising.