Murdock MacKinnon was a Canadian politician and served as the 11th Lieutenant Governor of Prince Edward Island.
MacKinnon was born in Brooklyn, Prince Edward Island to parents of Scottish descent, Lauchlin MacKinnon and Mary MacDonald.
He received his higher education from Prince of Wales College and then became a farmer. In the July 28, 1897 General Elections, MacKinnon was elected to represent the Conservative Party in the 4th Kings District in the Provincial Legislature. From that point until the 1919 General Elections, MacKinnon was continuously re-elected and retained his seat in the Legislature.
Between 1911 to 1919, he served as Commissioner of Agriculture and Provincial Secretary Treasurer in the provincial cabinet.
On September 8, 1919, Murdoch MacKinnon was appointed Lieutenant Governor of Prince Edward Island and served in that capacity until 1924. He is best known for making constitutional history in the province in 1923 for refusing his assent to the Church Union Bill.