Nederlek is a former municipality in the western Netherlands, in the province of South Holland. Since 2015 it has been a part of the municipality of Krimpenerwaard.
The former municipality covered an area of 31.24 km² of which 3.42 km² was covered by water. It was formed on 1 January 1985, by the amalgamation of the municipalities Krimpen aan de Lek and Lekkerkerk. Its name means "Lower Lek", a reference to its location on the Lek River.
There is no town called Nederlek; the former municipality consisted of the population centres Krimpen aan de Lek and Lekkerkerk. The last town gained notoriety in 1980 when a large amount of toxic waste was found underneath a residential area built in the 1970s. The cost of cleaning up the mess ran up to 188 million guilders.