In some bicameral parliaments of a Westminster System, the House of Commons has historically been the name of the elected lower house. The Commons generally holds much more power than the upper house (the senate or House of Lords). The leader of the majority party in the House of Commons usually becomes the prime minister.

Historically, "the commons" were an estate in a traditional pre-Enlightenment European government which typically divided the governance of an area between "estates" of society. Other estates included the clergy, nobles, merchants and knights. The word "commons" has at times been confused with the word "commoner", but they are very different in this context. The House of Commons was created to serve as the political outlet for this "commons" class, while the elite estates were represented in the House of Lords. The House of Commons was thus elected by the people while members of the upper house were appointed on the basis of various forms of elite "merit", such as wealth, family, or prestige.

States with a House of Commons base their democratic systems upon this original British house of parliament (it is thus occasionally called "the mother of parliaments"). Many such places were part of the British Empire, and are now part of the Commonwealth of Nations. There are only two existing Houses of Commons. The existing House of Commons are the:

• British House of Commons (at the Palace of Westminster, London)
• Canadian House of Commons (on Parliament Hill, in Ottawa)

Three historical bodies have used this name in Ireland, the

• House of Commons of Ireland (abolished in 1801)
• House of Commons of Southern Ireland (1921-1922)
• House of Commons of Northern Ireland (1921-1972)

The name was never used for for Australian House of Representatives or the New Zealand House of Representatives.

See also

• House of Representatives
• Chamber of Deputies
• House of Assembly
• House of Keys
• Legislative Assembly
• National Assembly
• Lok Sabha