John Diefenbaker leads the Progressive Conservative Party of Canada to a stunning upset in the 1957 Canadian federal election, ending 22 years of Liberal Party government.

John George Diefenbaker was the 13th prime minister of Canada, serving from 1957 to 1963. He was the only Progressive Conservative party leader between 1930 and 1979 to lead the party to an election victory, doing so three times, although only once with a majority of the seats in the House of Commons.

The Progressive Conservative Party of Canada was a centre to centre-right federal political party in Canada that existed from 1942 to 2003.

The 1957 Canadian federal election was held June 10, 1957, to select the 265 members of the House of Commons of Canada of the 23rd Parliament of Canada. In one of the greatest upsets in Canadian political history, the Progressive Conservative Party, led by John Diefenbaker, brought an end to 22 years of Liberal rule, as the Tories were able to form a minority government despite losing the popular vote to the Liberals.

The Liberal Party of Canada is a federal political party in Canada. The party espouses the principles of liberalism, and generally sits at the centre to centre-left of the Canadian political spectrum, with their main rival, the Conservative Party, positioned to their right and the New Democratic Party positioned to their left. The party is described as "big tent", practising "brokerage politics", attracting support from a broad spectrum of voters. The Liberal Party is the longest-serving and oldest active federal political party in the country, and has dominated the federal politics of Canada for much of its history, holding power for almost 70 years of the 20th century. As a result, it has sometimes been referred to as Canada's "natural governing party".