William Clarke McKinnell (September 29, 1873[1] – October 27, 1939[2]) was a politician in Manitoba, Canada.

[3] He registered with the Pharmaceutical Society of Great Britain as an apprentice to his father, a Northampton chemist, but abandoned this pursuit[citation needed] to go to Canada in 1892.

Running as a Farmer candidate, he defeated Liberal incumbent Arthur Lobb[1] by a single vote (978 to 977) in the Rockwood constituency.

The UFM unexpectedly won a majority of seats in this election, and formed government as the Progressive Party.

McKinnell served as a backbench supporter of John Bracken's government.