Ønslev is a village 10 kilometres (6.2 mi) north of Nykøbing on the Danish island of Falster. In January 2024 it had a population of 389.

The name is made up of the man's name "Øthan" and "lef", hereditary estate. It is first documented in the Danish Census Book (1231) as "Othænslef".

There is evidence the area has been inhabited since prehistoric times. When the nearby motorway was under construction, a passage grave and two settlements were discovered, one from the Bronze Age, the other from the Iron Age.

Ønslev Church stands alone about half a kilometer to the east of the village. Dating from c. 1200, it is built in the Early Gothic style.

In 1694, the parishes of Ønslev and Eskilstrup were combined into one as Ønslev–Eskildstrup. Under the State sale of 1766, the entire parish was purchased by Johan Christopher von Westen, governed by Vestenborg Manor. From the beginning of the 19th century, many farms came into private ownership leading families to establish themselves in the village. There were two large farms, 13 medium-size farms and 20 houses in the village by the end of the century. The first school was established in 1807, the second in 1924 and since 1954 the villages's children have attended the new school in Eskilstrup. The brewery, Ønslev Bryggeri, founded in 1880, was closed some years ago. At the beginning of the 20th century, the market gardener P. Damgaard produced mainly tomatoes, cucumbers and melons in his 12 greenhouses.

The village now depends largely on Eskilstrup, 3 km to the east, for its school, activities, shops and services.

• Jørgen Balthasar Dalhoff (1800–1890), goldsmith

• Media related to Ønslev at Wikimedia Commons