According to tradition, the party with the second most seats becomes the Official Opposition. Its head becomes the leader of the Opposition.

To have official party status in the Commons and obtain funding for research, a party must win at least 12 seats.

During each fiscal year, certain days are set aside for the Opposition to debate issues it chooses. The Opposition can also use these days to request a vote in the House on any matter it chooses. The party forming the government, however, decides the days granted to the Opposition.