The Twelfth Canadian Ministry was the first cabinet chaired by Prime Minister William Lyon Mackenzie King. It governed Canada from 29 December 1921 to 28 June 1926, including the 14th Canadian Parliament and most of the 15th. The government was formed by the Liberal Party of Canada. Mackenzie King was also Prime Minister in the Fourteenth and Sixteenth Canadian Ministries.

The 15th Canadian Parliament was in session from 7 January 1926, until 2 July 1926. The membership was set by the 1925 federal election on 29 October 1925, and it changed only somewhat due to resignations and by-elections until it was dissolved prior to the 1926 election.