The Official Australian Opposition is referred to simply as The Opposition; the title Her Majesty's Loyal Opposition, used in some other Commonwealth Realms, rarely appears in Australia. It is in practice more common to refer to the Opposition simply by the party name.

The Opposition in Australia fulfils the same function as the official opposition in other Commonwealth of Nations monarchies. It is seen as the alternative government and the existing administration's main opponent at a general election. By convention, the Opposition Leader comes from the House of Representatives, as does his deputy, although the Government and Opposition will also both have leaders in the Senate. The current leader of the Opposition in the Senate is Senator Chris Evans.

The present Opposition at a Federal level is the Australian Labor Party led by Kim Beazley.

The Official Opposition at the level of the States and Territories are:

• Australian Capital Territory: Liberal Party, led by Brendan Smyth.
• New South Wales: Liberal/National Coalition, led by John Brogden.
• Northern Territory: Country Liberal Party, led by Terry Mills.
• Queensland: National Party, led by Lawrence Springborg.
• South Australia: Liberal Party, led by Rob Kerin.
• Tasmania: Liberal Party, led by Rene Hidding.
• Western Australia: Liberal/National Coalition, led by Colin Barnett.

See also Official Opposition Shadow Cabinet.