John Williamson (c. 1730 – c. 1803), more commonly known by the nickname Johnnie Notions (pronounced [ˌdʒoni ˈnoʃəns], JOH-nee-NOH-shəns) was a self-taught physician from Shetland, Scotland, who independently developed and administered an inoculation for smallpox to thousands of patients in Shetland during the late 18th century. Despite having only an elementary education and no formal medical background, the treatment he devised had an extremely high success rate, resulting in the immunisation of approximately 3,000 people and the saving of many lives, which had a significant effect on the demographics of the Shetland population at the time. He is reputed not to have lost a single patient.