John Michael Newsom-Davis (18 October 1932 – 24 August 2007) was a neurologist who played an important role in the discovery of the causes of, and treatments for, Myasthenia gravis, and of other diseases of the nerve-muscle junction, notably Lambert-Eaton myasthenic syndrome and acquired neuromyotonia.
Regarded as "one of the most distinguished clinical neurologists and medical scientists of his generation," he died in a car accident in Adjud, Romania, having visited a neurological clinic in Bucharest earlier the same day.