Koen Jozef van Velsen (°Hilversum, 17 July 1952) is a Dutch architect. He became ‘rijksbouwmeester’ in 1915.
Van Velsen completed his formal education at the Academie van de Bouwkunst (Academy of Architecture) in Amsterdam in 1983.
His work employs a contextual design approach, free of a personal esthetic. Van Velsen’s early work consisted mostly of additions and renovations to existing buildings. He typically incorporated contemporary elements into a historical framework, transforming structures in a way that earned him a reputation for creating “light and transparent” designs.