Kuok's brother, Philip Kuok Hock Khee was a former Malaysian Ambassador to Germany, Yugoslavia, Netherlands, Belgium, Luxembourg and Denmark. Philip married Eileen Kuok and had two sons and two daughters. Philip Kuok died in 2003. Another brother, William Kuok Hock Ling, was a member of the Malayan Communist Party and was killed during the Malayan Emergency in 1952. According to his memoir, Kuok described that of all the brothers, his mother Zheng Ge Ru doted on and adored William the most, and was heartbroken when she received news of William's death.