Robert Whytt (6 September 1714 – 15 April 1766) was a pioneering Scottish physician and natural philosopher who worked during the Scottish Enlightenment. After studying medicine both in Edinburgh and London, he returned to Edinburgh and became a fellow of the Royal College of Physicians of Edinburgh in 1738. He demonstrated the importance of the central nervous system on movement, and his work on nervous diseases was published in On Nervous, Hypochondria, or Hysteric Diseases. He clarified that involuntary motions were dependent on stimuli applied to nerves or the nerves of muscles, published in his book On the Vital and other Involuntary Motions of Animals. His work on pupillary light reflex led it being named the Whytt Reflex.