Thomas Alexander Crerar (June 17, 1876-April 11, 1975) was a western Canadian politician and a leader of the short lived Progressive Party of Canada. He was born in Molesworth, Ontario, and moved to Manitoba at a young age.

Crerar rose to prominence as leader of the Manitoba Grain Growers association in the 1910s. Although he had no experience as an elected official, he was appointed as Minister of Agriculture in Robert Laird Borden's Union government on October 12, 1917, to provide a show of national unity during the first World War. He was easily elected to the Canadian House of Commons for Marquette in the election of 1917.

On June 6, 1919, Crerar resigned from his position in protest against the high tariff policies of the Conservative-dominated government. He was strongly in favour of free trade with the United States, which would have benefited the western farmers.

In 1920, he was selected as leader of the Progressive Party. In the 1921 election, he led the party to a landslide victory in western Canada, giving them 65 seats in the Canadian parliament. Crerar failed to hold the party together, however. He resigned as leader in 1922, and the party collapsed shortly thereafter.

Crerar spent some time in the private sector before returning to politics in 1929, as a member of Mackenzie King's Liberals. Though once again not holding a seat in parliament, he was appointed Minister of Railways and Canals on December 30, 1929, and won a by-election in Brandon on February 5, 1930. King's government was defeated in the general election which followed, however, and Crerar was personally defeated in his riding.

He returned to parliament in 1935, as the member for the northern Manitoba riding of Churchill. He was once again appointed to King's cabinet, serving as Minister of Immigration and Colonization, Minister of Mines, Minister of the Interior and Superintendent-General of Indian Affairs from October 23, 1935 to November 30, 1936. On December 1, 1936, he was removed from most of his responsibilities and became simply Minister of Mines and Resources, holding the position until April 17, 1945.

Crerar was appointed to the Canadian Senate on April 18, 1945, and remained a Senator until his retirement on May 31, 1966. In 1973 he was made a Companion of the Order of Canada.