Duke of Westminster is a title in the Peerage of the United Kingdom. It was created by Queen Victoria in 1874 and bestowed upon Hugh Grosvenor, 3rd Marquess of Westminster. It is the most recent dukedom conferred on someone not related to the British royal family.

Hugh Lupus Grosvenor, 1st Duke of Westminster,, styled Viscount Belgrave between 1831 and 1845, Earl Grosvenor between 1845 and 1869, and known as The Marquess of Westminster between 1869 and 1874, was an English landowner, politician and racehorse owner. He inherited the estate of Eaton Hall in Cheshire and land in Mayfair and Belgravia, London, and spent much of his fortune in developing these properties. Although he was an MP from the age of 22, and then a member of the House of Lords, his main interests were not in politics, but rather in his estates, in horse racing, and in country pursuits. He developed the stud at Eaton Hall and achieved success in racing his horses, winning the Derby on four occasions.