Haslev is a railway town in the southern part of the island of Zealand, Denmark, located about 60 km (37 mi) southwest of Copenhagen.

Haslev started out being a small village named Hasle with a few houses and streets surrounding the church.

During the 20th century Haslev grew rapidly, becoming a center for the Church Association for the Inner Mission in Denmark.

In the early 1970s and onwards, an entrepreneur named Ole Christiansen founded whole new neighbourhoods of one-family houses with an attached garden at a low expense.

Nobel-Prize winner Jens Christian Skou studied at Haslev Gymnasium (college) in his youth.