William Grosvenor, 3rd Duke of Westminster

William Grosvenor, 3rd Duke of Westminster (* December 23, 1894, † February 22, 1963 ) was the son of Henry and grandson of Hugh Grosvenor Grosvenor, 1st Duke of Westminster. His mother, Dora was great-granddaughter of William IV

At his birth he suffered a mental disability. He inherited his title and the associated property in Westminster by his cousin, Hugh Grosvenor, 2nd Duke of Westminster. After his mother's death he lived with his stepmother, Rosamund, in a small house in southern England. After her death, he lived with a nurse in Bath, Somerset.

The Duke died in 1963 at the age of 68, unmarried and childless. His titles were inherited by his cousin Gerald Hugh Grosvenor, 4th Duke of Westminster, the eldest son of his half- uncle.