Jacob "Jaap" Oudkerk (born 2 August 1937) is a retired cyclist from the Netherlands. He competed in the 4000 m team pursuit at the 1960 and 1964 Summer Olympics and finished in fifth and third place, respectively. He was also active in motor-paced racing. After winning the world championships in the amateurs category in 1964 he turned professional and won three more world championship medals, including a gold in 1969. He was the husband of Marianne Heemskerk, a Dutch Olympic swimmer.