Khoo Kay Kim was born to Peranakan Chinese parents in Kampar, Perak, Malaysia on 28 March 1937. He received a B.A., M.A., and a Ph.D. in 1959, 1967, and 1974 respectively from the University of Malaya. His doctoral thesis was entitled The Beginnings of Political Extremism in Malaya 1915-1935 (1974), where he was supervised by Kennedy G. Tregonning, the Raffles Professor of History at the University of Malaya.