| Honorific Prefix: | The Honourable |
| John Stewart McLennan | |
| Office: | Member of the Senate of Canada for Sydney, Nova Scotia division |
| Term Start: | 10 February 1916 |
| Term End: | 15 September 1939 |
| Birth Name: | John Stewart McLennan |
| Birth Date: | 1853 11, df=yes |
| Birth Place: | Montreal, Canada East |
| Death Place: | Ottawa, Ontario, Canada |
| Residence: | Sydney, Nova Scotia |
| Profession: | industrialist, publisher |
| Party: | Conservative |
John Stewart McLennan (5 November 1853 – 15 September 1939) was a Conservative member of the Senate of Canada. He was born in Montreal, Quebec and became an industrialist and publisher.
The son of Hugh McLennan and Isabella Stewart, he was educated at the High School of Montreal, McGill University, and Concordia, and moved to Sydney, Nova Scotia. In 1904, he bought the Sydney Post (later the Post-Record). McLennan was married twice: to Louise Bradley in 1881 and to Grace Henoys Tytus in 1915. He was a director of Dominion Iron and Steel Company and the Dominion Coal Company. McLennan was the author of Louisbourg, from its foundation to its fall, 1713-1758, https://books.google.com/books?id=pgu6reH9yjQC&pg=PA12 first published in 1918.[1]
He was appointed to the Senate on 10 February 1916 for the Sydney, Nova Scotia division following nomination by Prime Minister Robert Borden. McLennan remained a Senator until his death on 15 September 1939.