Platon Hryhorovych Kostyuk (Ukrainian: ?????? ?????????? ??????) (20 August 1924 – 10 May 2010) was a Ukrainian physiologist, neurobiologist, electrophysiologist, and biophysicist.
He was a member (academician) of the National Academy of Sciences (NAS) of Ukraine and the Russian Academy of Sciences.
He was also a director of the Bogomoletz Institute of Physiology and the International Center of Molecular Physiology NAS of Ukraine; chair of the Moscow Institute of Physics and Technology, Kiev branch, vice-president of the NAS of Ukraine, and chairman of the Verkhovna Rada of the Ukrainian SSR.