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.

The system is a series of procedures for operating a legislature. It is used, or was once used, in the national legislatures and subnational legislatures of most Commonwealth and ex-Commonwealth nations upon being granted responsible government, beginning with the first of the Canadian provinces in 1848 and the six Australian colonies between 1855 and 1890.

There are other parliamentary systems whose procedures differ considerably from the Westminster system.

Important features of the Westminster system include the following, although not all of the following aspects have been preserved in every Westminster-derived system:^{[citation needed]}

Most of the procedures of the Westminster system have originated with the conventions, practices and precedents of the Parliament of the United Kingdom, which are a part of what is known as the Constitution of the United Kingdom. Unlike the uncodified British constitution, most countries that use the Westminster system have codified the system in a written constitution.

Coordinates: 51°29′58″N 0°08′00″W / 51.4995°N 0.1333°W / 51.4995; -0.1333

Westminster /ˈwɛsᵗmɪnstə/ is an area of central London, within the City of Westminster, England. It lies on the north bank of the River Thames, southwest of the City of London and 0.5 miles (0.8 km) southwest of Charing Cross. It has a large concentration of London's historic and prestigious landmarks and visitor attractions, including the Palace of Westminster, Buckingham Palace, Westminster Abbey, and Westminster Cathedral.

Historically a part of Middlesex, the name Westminster was the ancient description for the area around Westminster Abbey – the West Minster, or monastery church, that gave the area its name – which has been the seat of the government of England (and later the British government) for almost a thousand years. Westminster is the location of the Palace of Westminster, a UNESCO World Heritage Site which houses the Parliament of the United Kingdom.

The name Westminster describes the area around Westminster Abbey and Palace of Westminster. Its name derives from the West Minster, or monastery church, west of the City of London's St Paul's. The area has been the seat of the government of England for almost a thousand years. The name is also used for the larger City of Westminster which covers a wider geographical area; and, since 1965, has included the former boroughs of Marylebone and Paddington.