John Alexander Macdonald, PC (April 12, 1874 – November 15, 1948) was a Canadian politician.

Born in Tracadie, Prince Edward Island, the son of John Charles Macdonald,[1] he represented 3rd Kings in the Legislative Assembly of Prince Edward Island from 1908 to 1915 and from 1923 to 1925 as a Conservative member.

In 1935, he was appointed to the Senate of Canada representing the senatorial division of Cardigan, Prince Edward Island.

[1] His son John Augustine also represented the riding of King's in the House of Commons.

John Augustine's wife Margaret Mary was the first woman from Prince Edward Island to serve in the House of Commons.