| Honorific-Prefix: | The Honourable |
| John Graham Haggart | |
| Constituency Mp: | Lanark South |
| Parliament: | Canadian |
| Predecessor: | Alexander Morris |
| Successor: | Adelbert Edward Hanna |
| Term Start: | 1872 |
| Term End: | 1913 |
| Birth Date: | November 14, 1836 |
| Birth Place: | Perth, Upper Canada |
| Death Place: | Ottawa, Ontario, Canada |
| Party: | Conservative |
John Graham Haggart, (November 14, 1836 - March 13, 1913) was a Canadian politician.
Haggart served as a Member of Parliament from 1872 to 1913. This forty-year period of service in the Commons is the second-longest in Canadian history, exceeded only by Wilfrid Laurier, whose period of service (1874-1919) mostly overlaps with Haggart's.[1] He was appointed as Postmaster General, serving in the cabinets of John A. Macdonald and John Abbott until 1892, when he switched portfolios, serving as Minister of Railways and Canals until the defeat of the Conservative government in 1896.
Prior to being elected to the House of Commons, Haggart was elected Mayor of Perth, Ontario three times: in 1867, 1869 and 1871.
There is a John Haggart fonds at Library and Archives Canada.[2]