The 2004 Canadian federal election was held on June 28, 2004, to elect members to the House of Commons of Canada of the 38th Parliament of Canada. The Liberal government of Prime Minister Paul Martin lost its majority but was able to continue in office as a minority government after the election. This was the first election contested by the newly amalgamated Conservative Party of Canada, after it was formed by the two right-of-centre parties, the Progressive Conservative Party and the Canadian Alliance.

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 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".