Nykøbing Sjælland is a town in Denmark, located in the northern part of Odsherred on the island of Zealand. Nykøbing Sjælland has a population of 5,500 and is a popular seaside resort in the summer season.
Nykøbing Sjælland is one of the oldest towns on Zealand, first mentioned in the last part of the 13th century, although the local church dates from the first half of this 13th century. The town was destroyed by followers of Marsk Stig in 1290, and it has since been swept by several fires. The town and surrounding land was pawned by the crown to the Diocese of Roskilde in 1370, but was redeemed by Queen Margaret I. In the Middle Ages, the town was known for its harbour and its role in the fishing of herring. It received a charter in 1443 after which commerce replaced fishing as the main occupation. A school teaching in Latin was established in 1590, and replaced by a school teaching in Danish by 1740. At this time, the population was a mere 350, making it one of Zealand's smallest towns.
Nykøbing Sjællandis not to be confused with at least two other towns in Denmark called Nykøbing: Nykøbing Falster and Nykøbing Mors.