Flade, Catholic secondary school in St. Gallen, Switzerland

Flade is a Catholic secondary school in central St. Gallen spread across three buildings named Kloster, Gallus, and Notker. Each location serves a specific function in the school's operations and houses different grade levels and learning areas.

The monastery school closed in 1805 when the abbey was dissolved. In 1808/09 a 'Gymnasium katholischer Fundation' opened in the former monastery building, with Alois Vock as first rector, alongside a 'Bürgerschule' with boarding house. Renamed Katholische Kantonsschule in 1834/35, it became a Catholic cantonal secondary school for boys in 1856 after the city's schools merged.

The school maintains separate learning spaces for boys and girls in some buildings, while offering mixed classes in others, reflecting different educational philosophies. This structure shapes how students experience their time here and interact with their peers.

The Kloster building occupies the south wing of the St. Gallen abbey church, where the abbey library is also housed; the Gallus building stands on Moosbruggstrasse outside the monastery walls, and the Notker building lies in the Neudorf district in the east of the city. The canton ended its subsidy from the 2016 school year, and the city of St. Gallen raised its contribution to a maximum of 4.3 million Swiss francs through 2018/19.

The school has been called Flade in popular speech since the 19th century, but it only adopted the name officially in 2008, when it also added it to its logo. Its full name since 2009 is Flade – Katholische Kantonssekundarschule.