De Lek was a heerlijkheid (manor) and municipality in the Netherlands, located in the province South Holland.
The first Lord of the Lek is reported to be a younger brother of Diederik II of Brederode.
After his death it went to his younger brother, Louis of Nassau, Lord of De Lek and Beverweerd.
The municipality covered the river Lek between Ammerstol and Krimpen aan den IJssel, and some islands and surrounding lands.
Its area was 5.99 km2, of which 1.24 km2 was land, and it contained several small fisherman's huts and boathouses, but it had no inhabitants.