Lennik (Dutch pronunciation: [ˈlɛnɪk]) is a municipality located in the Belgian province of Flemish Brabant.

The municipality comprises the towns of Sint-Kwintens-Lennik, Sint-Martens-Lennik, Eizeringen and Gaasbeek.

The total area is 30.80 km2 which gives a population density of 282 inhabitants per km2.

On its territory is the national Gaasbeek Castle museum.

This Flemish Brabant location article is a stub.