thumb|150px|Hon. John Thomas Haig, PC
John Thomas Haig, (December 15, 1877 – October 23, 1962) was a politician in Manitoba, Canada. He served as parliamentary leader of the Manitoba Conservative Party in 1921–22.
Born in Colborne, Ontario,
Haig was first elected to the Legislative Assembly of Manitoba for Assiniboia in 1914. He was soundly defeated in the Liberal landslide of 1915, but returned to the legislature in 1920 at the head of the Conservative Party list in Winnipeg. (Winnipeg elections were determined by a form of proportional representation at this time.)
Conservative leader R.G. Willis was unable to win a seat in the 1920 election, and Haig was called to lead the eight-member caucus in parliament. He ran for the party's leadership in April 1922, but was defeated by Major Fawcett Taylor.
Haig was re-elected to the legislature in 1922, 1927 and 1932,
Haig died in Winnipeg at the age of 84.
His son James Campbell Haig also served in the Senate.