Slagelse, a town in east Denmark, is in Slagelse municipality on the island of Zealand. It is about 100 km (62 mi) southwest of Copenhagen. The population is 32,133 (1 January 2012).
In the 11th century, Slagelse had a mint and was an important trading center. The city has an 11th-century church, and nearby is Trelleborg, a Viking fortress.
Hans Christian Andersen studied in the grammar school in this city for a few years but described it as a "nuisance".
Slagelse is twinned with Aberdare, Wales and Stargard Szczeciński, Poland.