Church of the Assumption, Baroque church building in Žatec, Czech Republic

The Church of the Assumption is a Gothic hall church with a main nave and two narrower side aisles, a polygonal presbytery, and a Baroque double-tower west facade. A massive south bell tower with a bulbous cupola stands at its side, and the octagonal Chapel of St. John of Nepomuk adjoins the southwest corner.

A late Romanesque basilica with a westwork was built here in the early 13th century, and its masonry survives in the west facade. A Gothic hall church followed from 1336, when John of Luxembourg granted market and river tolls; the south tower was founded in 1380. After the 1738 fire, the west front was rebuilt as a Baroque twin-tower facade, and the wooden bell tower was replaced in stone in 1770–1773.

The church is dedicated to the Assumption of Mary, celebrated as a high feast on 15 August; in earlier times the Portiuncula feast followed on 2 August. The main altar painting of the Assumption was made by Prague painter Anton Stevens in 1668 and restored in Vienna in 1838. The chapel of St John of Nepomuk holds a vault with a 1746 fresco of scenes from his life by Josef Anton Gentsch.

The church stands on Hošťálkovo Square just behind the Kněžská (Priest's) Gate, the former main entrance to the walled town, and belongs to the Litoměřice diocese. It reopened to the public on 3 June 2007 after work securing the vaults and repainting the interior. The south bell tower, rebuilt in stone in 1767–1773, is entered from inside.

The south bell tower was only half finished in the 14th century; its upper bell storey was built of wood until Johann Paul Losch replaced it with the present massive masonry tower in 1770–1773. The bells cast in Prague in 1768 were hung there in 1773.