National Westminster Bank, trading as NatWest, is a major retail and commercial bank in the United Kingdom based in London, England. It was established in 1968 by the merger of National Provincial Bank and Westminster Bank. In 2000, it became part of The Royal Bank of Scotland Group, which was re-named NatWest Group in 2020. Following ringfencing of the group's core domestic business, the bank became a direct subsidiary of NatWest Holdings; NatWest Markets comprises the non-ringfenced investment banking arm. The British government currently owns 35% of NatWest Group after spending £45 billion bailing out the lender in 2008; the proportion at one point was 54.7%. NatWest International is a trading name of RBS International, which also sits outside the ringfence.

National Provincial Bank was a retail bank which operated in England and Wales. It was created in 1833 as National Provincial Bank of England, and expanded largely by taking over a number of other banks. Following the transformative acquisition of Union Bank of London in 1918, it changed its name to National Provincial and Union Bank of England, then in 1924 shortened its name again to National Provincial Bank. It further acquired Coutts Bank in 1920, Grindlays Bank in 1924, Isle of Man Bank in 1961, District Bank in 1962, thus becoming one of the "Big Five" that dominated the UK banking sector for much of the 20th century, together with Barclays Bank, Lloyds Bank, Midland Bank and Westminster Bank. On 1 January 1970, it completed its merger with Westminster Bank to form National Westminster Bank.