The Leader of the Opposition in Malaysian Federal Politics is a Member of Parliament in the Dewan Rakyat (House of Representatives). By convention, the position is held by the leader of the political party not in government that has the most seats in the House. When in parliament, the Leader of the Opposition sits on the left-hand side of the centre table, in front of the Opposition and opposite the Prime Minister. The Opposition Leader is elected by the minority party of the House according to its rules. A new Opposition Leader may be elected when the incumbent dies, resigns, or is challenged for the leadership.
Malaysia is a constitutional monarchy with a parliamentary system and is based on the Westminster model. The Opposition is an important component of the Westminster system, with the Opposition directing criticism at the Government's policies and programs, give close attention to all proposed legislation and attempts to defeat and replace the Government. The Opposition is therefore known as the 'government in waiting' and it is a formal part of the parliamentary system. Due to the domination of the Barisan Nasional (and its predecessor, the Alliance) coalition of the parliament since independence, this perception is generally not acknowledged by Malaysians, though since the 2008 elections, Anwar Ibrahim has declared that the Opposition is the 'government in waiting'. Note that this article uses the term government as it is used in parliamentary systems, i.e. meaning the administration, majority party or coalition in parliament or the cabinet, rather than the state.
To date there have been 10 Opposition Leaders, none of whom have served terms as Prime Minister. The current Leader of the Opposition is Wan Azizah Wan Ismail of the People's Justice Party, following an election of the new Parliamentary PKR Leader by caucus and other minority party's MPs on 18 May 2015.