The 1878 Canadian federal election was held on September 17, 1878, to elect members of the House of Commons of the 4th Parliament of Canada. It resulted in the end of Prime Minister Alexander Mackenzie's Liberal government after only one term in office. Canada suffered an economic depression during Mackenzie's term, and his party was punished by voters for it. The Liberals' policy of free trade also hurt their support with the business establishment in Toronto and Montreal.

Alexander Mackenzie was a Canadian politician who served as the second prime minister of Canada, in office from 1873 to 1878.