Nieuwkoop is a town and municipality in the western Netherlands, in the province of South Holland. The municipality was enlarged on 1 January 2007, through the amalgamation of Liemeer and Ter Aar. The municipality now covers an area of 91.16 km2 (35.20 sq mi) of which 13.11 km2 (5.06 sq mi) is water. Its population was 29,151 in 2021.

Arjan van der Laan is a Dutch former professional footballer, who played as a midfielder. He is the current head coach of the seventh-tier Tweede Klasse club RKSV Altior from Langeraar.