William Canniff, (born in Thurlow, Upper Canada, 20 June 1830; died in Belleville, Ontario 18 October 1910) was a surgeon, public health pioneer, historian and advocate of Canadian nationalism.

[1][2] Dr. William Canniff trained in medicine in Canada, the US, Great Britain and Europe prior to settling in Belleville where he practiced surgery.

[2] Following brief periods of study and practice in New York, London, Edinburgh, Dublin, and Paris, Canniff returned to Belleville, Ontario, joining the faculty of the Victoria School in 1859 as a lecturer in pathology.

[4] Throughout his tenure as chief medical officer for Toronto, Canniff met resistance from physicians who defied his department's requirement for infectious disease reporting, arguing that the extra effort needed to do this went uncompensated.

[5]: 36  At the same time, city council continued to pressure Canniff for his failure to collect comprehensive disease surveillance statistics, criticizing his lack of impact on the growing spread of infectious illnesses.