Archibald McKellar MacMechan FRSC (June 21, 1862 – 7 August 1933) was a Canadian academic at Dalhousie University and writer. His works deal mainly with Nova Scotia and its history. The Halifax Disaster (Explosion) was an official history of the Halifax Explosion.
Born in Kitchener, Ontario, he is credited with reviving Herman Melville's reputation in North America. He had written to Melville in 1889, right at the end of his life.
He was awarded the Lorne Pierce Medal in 1932.
He was a long-term member of the Royal Nova Scotia Historical Society.