Lansdowne House now 9 Fitzmaurice Place is the remaining part of an aristocratic English town house building to the south of Berkeley Square in central London, England. The initial name was for two decades Shelburne House, then its title matched its owning family's elevation to a higher peerage in 1784. In the mid to late 19th century, it was frequently let, as a whole, to families of very high wealth or income, such as Lord Rosebery and Hannah de Rothschild of Mentmore Towers from 1878 to 1890. Some of its 18th-century interiors, among the best in London, were taken elsewhere. It was at different times leased by three 19th century British prime ministers, and William Waldorf Astor, 1st Viscount Astor of Cliveden House, widely believed to be the richest man in America at the time of his tenancy (1891–1893) and also by Harry Gordon Selfridge in the 1920s. Landsdowne's heirs sold the property in 1929, two years after the death of the 5th Marquess, a prominent government frontbencher.

In British usage, the term townhouse originally referred to the opulent town or city residence of a member of the nobility or gentry, as opposed to their country seat, generally known as a country house or, colloquially, for the larger ones, stately home. The grandest of the London townhouses were stand-alone buildings, but many were terraced buildings.