Jacobus Gijsbert "Koos" Rietkerk (14 December 1927 – 20 February 1986) was a Dutch politician of the People's Party for Freedom and Democracy (VVD) and jurist. Rietkerk attended the Christian Gymnasium in Haarlem from April 1940 until May 1946 and applied at the Leiden University in June 1946 majoring in Law and obtaining an Bachelor of Laws degree in June 1948 and worked as a student researcher before graduating with a Master of Laws degree in July 1952. Rietkerk worked as a lawyer in Haarlem from January 1953 until October 1956 and also worked as a civil servant for the Immigration and Naturalisation Service (IND) of the Ministry of Justice from January 1953 until October 1956. Rietkerk worked as legal advisor for the Municipalities association (VNG) from October 1956 until January 1959.