Maassluis ([maˑˈslœy̆s] ( listen)) is a town in the western Netherlands, in the province of South Holland. The municipality had a population of 31,980 in 2010, and covers an area of 10.11 km2 (3.90 sq mi) of which 1.51 km2 (0.58 sq mi) water.
It received city rights in 1811. It was the setting for the Dutch cult classic, Spetters, filmed by noted director Paul Verhoeven there in 1980.