Cornelis "Kees" van Geelkerken (Dutch pronunciation: [kɔrˈneːlɪs fɑŋ ˈɣeːlkɛrkə(n)];[a] 19 March 1901 – 29 March 1976) was a Dutch fascist political leader and Nazi collaborator.

Van Geelkerken was born in 1901 to a Dutch family in Molenbeek-Saint-Jean, Belgium, and grew up in Utrecht.

He gravitated toward fascism in the 1920s while working as a municipal employee in Zeist and Utrecht.

Van Geelkerken co-founded the far-right National Socialist Movement in the Netherlands (NSB) with Anton Mussert in 1931.

After the war, he was tried in the Bijzonder Gerechtshof ("Special Court of Justice") and sentenced to life imprisonment.