The New Democratic Party.
As a result of Canada's federal election of May 2, 2011, the New Democratic Party (NDP) now forms Her Majesty's Loyal Opposition. The Honourable Thomas Mulcair, Leader of the NDP and MP for Outrement, is the Leader of the Opposition.
In the Federal Government of the United States, the opposition party is the Republican Party.
The Labour Party is the official opposition party to the Conservative/Liberal Democrat coalition government.
In Canada, Her Majesty's Loyal Opposition (popularly known as the Official Opposition) is simply the political party which holds the most seats in the House of Commons (or a provincial assembly) next to the dominant party. Usually it is the second-largest party. The Official Opposition may be either a narrowly defined party or a coalition. Currently, the New Democratic Party of Canada forms the official opposition in Canada, for the first time in its history. It has held this status since 2011, when it won a party record 103 seats in the House of Commons - second to the Conservative Party's 166 seats.
Parti québécois
Yes, this past Federal Election saw them form the official opposition for the first time in history.
The Australian Labor Party (ALP) - current federal officeholder Liberal Party National Party (these two make up the Coalition and the official Opposition The Greens
NDP
In a Parliamentary system, the Official Opposition is the second largest party in Parliament.
In Australia in 2010, the leader of the opposition is Tony Abbott, of the Liberal party of Australia.
Usually the government is under the control of a political party or a coalition of political party's. If your party does not have control of the government but does have seats in the parliament or senate then it is an opposition party. That is a party that opposes the government. The official opposition is the party with the second most seats in the house of commons.
The largest party in opposition is called the "Official Opposition," officially known as "Her Majesty's Loyal Opposition." As a result of Canada's federal election of May 2, 2011, the New Democratic Party (NDP) now forms Her Majesty's Loyal Opposition. The Honourable Nycole Turmel, Leader of the NDP, is the Leader of the Opposition. The Liberal Party has been reduced to minority third party status and the Bloc Québéois, which elected only four members, has lost official party status.