| Honorific-Prefix: | The Honourable |
| John George MacKay | |
| Order: | 20th |
| Office: | Lieutenant Governor of Prince Edward Island |
| Term Start: | October 6, 1969 |
| Term End: | October 21, 1974 |
| Predecessor: | Willibald Joseph MacDonald |
| Successor: | Gordon Lockhart Bennett |
| Governor General: | Roland Michener Jules Léger |
| Premier: | Alex Campbell |
| Office1: | MLA (Councillor) for 4th Prince |
| Predecessor1: | Horace Wright |
| Successor1: | Cleveland Baker |
| Term Start1: | July 4, 1949 |
| Term End1: | April 26, 1951 |
| Office2: | MLA (Assemblyman) for 4th Prince |
| Predecessor2: | Cleveland Baker |
| Successor2: | Max Thompson |
| Term Start2: | April 26, 1951 |
| Term End2: | May 30, 1966 |
| Birth Date: | 6 November 1893 |
| Birth Place: | Albany, Prince Edward Island |
| Death Place: | Charlottetown, Prince Edward Island |
| Nationality: | Canadian |
| Party: | Liberal |
| Children: | John Howatt, Audrey Beryl, Lois Rita, Sutherland Bruce (died at 22) and Phillis (died at seven months) |
| Residence: | Albany, Prince Edward Island |
| Occupation: | Farmer |
| Profession: | Politician |
| Cabinet: | Minister without Portfolio (1952-1955) Minister of Highways (1955-1959) acting Minister of Public Works and Highways (1967-1969) |
John George MacKay (November 6, 1893 - October 21, 1974[1]) was a farmer and political figure on Prince Edward Island. He represented 4th Prince in the Legislative Assembly of Prince Edward Island from 1949 to 1966 as a Liberal. MacKay was the 20th Lieutenant Governor of Prince Edward Island, serving from October 6, 1969, to October 24, 1974.
He was born in Albany, Prince Edward Island, the son of David MacKay and Almira Harvey, and was educated there. MacKay married Muriel Beatrice Boulter in 1918. He was president of the Tryon Dairying Company and the Tryon Farmers' Institute and also served as a director of the Provincial Swine Breeders' Association. MacKay served in the 10th Siege Battery with the Canadian Expeditionary Force during World War I. After the war, he continued his military service in the Canadian Militia as a sergeant in The Prince Edward Island Light Horse (now part of The Prince Edward Island Regiment (RCAC)).[2] He was a member of the provincial cabinet as a minister without portfolio in 1952 and as Minister of Highways from 1955 to 1959.[3] MacKay died in office at the Prince Edward Island Hospital in Charlottetown at the age of 80.