Osek (German: Ossegg) is a town in Teplice District in the Ústí nad Labem Region of the Czech Republic.

Salesiova výšina is a rock city of huge quartzite blocks, pillars and fissures west of the town proper.

The dissolution of the monastery was annulled in 1614 by Pope Paul V. During the Thirty Years' War, the Osek estate was confiscated by Protestants and sold to several buyers.

[5] Osek is located on the railway line heading from Děčín and Ústí nad Labem to Litvínov.

[9] Osek Festival is an annual event with fairground markets, demonstrations of traditional crafts and funfair attractions.

[5] The interior of the monastery Church of the Assumption of the Virgin Mary was decorated by painters Václav Vavřinec Reiner, Jan Kryštof Liška and Michael Willmann and sculptors Franz Anton Kern and Giacomo Antonio Corbellini.

It has two parts, the first one is the core with residential towers and a chapel, and the second one is a large complex surrounded by a wall with shooting turrets, dominated by a massive bergfried.