A member of parliament (MP) is the representative of the voters to a parliament. In many countries with bicameral parliaments, this category includes specifically members of the lower house, as upper houses often have a different title, such as senate, and thus also have different titles for its members, such as senator.

Members of parliament tend to form parliamentary groups (also called parliamentary parties) with members of the same political party.

Westminster system

The Westminster system is a democratic parliamentary system of government modelled after the politics of the United Kingdom. This term comes from the Palace of Westminster, the seat of the Parliament of the United Kingdom.

Australia

A member of parliament is a member of the House of Representatives, the lower house of the Commonwealth (federal) parliament. Members may use "MP" after their names; "MHR" is not used, although it was used as a post-nominal in the past. A member of the upper house of the Commonwealth parliament, the Senate, is known as a "Senator".

The Parliament of Canada (French: Parlement du Canada) is the federal legislative branch of Canada, seated at Parliament Hill in the national capital, Ottawa, Ontario. The body consists of the Canadian monarch, represented by a viceroy, the governor general; an upper house: the Senate; and a lower house: the House of Commons. Each element has its own officers and organization. The governor general summons and appoints each of the 105 senators on the advice of the Prime Minister of Canada, while the 338 members of the House of Commons—called members of parliament (MPs)—are directly elected by eligible Canadian voters, with each MP representing a single electoral district, commonly referred to as a riding.

By constitutional convention, the House of Commons is the dominant branch of parliament, the Senate and Crown rarely opposing its will. The Senate reviews legislation from a less partisan standpoint and the monarch or viceroy provides the necessary Royal Assent to make bills into law. The governor general also summons parliament, while either the viceroy or monarch can prorogue or dissolve parliament, the latter in order to call a general election. Either will read the Throne Speech. The most recent parliament, summoned by Governor General David Johnston on 2 June 2011, was the 41st since Confederation in 1867.