The Unionist Party was a centre-right historical political party in Canada, composed primarily of former members of the Conservative party with some individual Liberal Members of Parliament. It was formed in 1917 by MPs who supported the "Union government" formed by Sir Robert Borden during the First World War, who formed the government through the final years of the war, and was a proponent of conscription. It was opposed by the remaining Liberal MPs, who sat as the official opposition.