The Right Honourable James (Jimmy) Garfield Gardiner (November 30, 1883-January 2, 1962) was a farmer, politician, Premier of Saskatchewan, Canada, and minister in the Canadian Cabinet.

Jimmy Gardiner was first elected to the Legislative Assembly of Saskatchewan in 1914, and served as Minister of Highways (1922-26) in the government of Premier Charles A. Dunning from 1922 until succeeding Dunning as Premier in 1926. A highly partisan Liberal, his government lost its majority in the legislature in the 1929 election due to patronage scandals. Although the Conservative Party had won fewer seats, it was able to form a "co-operative government" with the support of some Progressive Party and independent Members of the Legislative Assmbly.

As Leader of the opposition, Gardiner railed against the bigotry of James Anderson's Conservative government, alleging that it was linked with the Ku Klux Klan. Gardiner defeated Anderson in the 1934 election, and became Premier a second time.

Gardiner left provincial politics the next year to join the federal cabinet of Liberal Prime Minister William Lyon Mackenzie King as Minister of Agriculture. He held that portfolio for twenty-two years until the 1957 federal election when the Liberal government was defeated.

Gardiner ran for the leadership of the Liberal Party of Canada at the 1948 Liberal leadership convention, but lost to Louis St. Laurent. He remained in the Canadian House of Commons until he lost his seat in the 1958 Diefenbaker sweep.

Saskatchewan's Gardiner Dam is named after him.