Žatec is a town in Louny District in the Ústí nad Labem Region of the Czech Republic. It has about 19,000 inhabitants. It lies on the Ohře river. Žatec is famous for an over-700-year-long tradition of growing Saaz noble hops used by several breweries. Žatec and the Landscape of Saaz Hops was included in the UNESCO World Heritage List in 2023. The historic town centre is well preserved and is protected by law as an urban monument reservation and partly also as an urban monument zone.

Louny District is a district in the Ústí nad Labem Region of the Czech Republic. Its capital is the town of Louny, but the most populated town is Žatec.