William Fitzalan, 9th Earl of Arundel, 6th Baron Maltravers (23 November 1417 – 1487) was an English nobleman.

His elder brother John Fitzalan, 7th Earl of Arundel, died on 12 June 1435.

The title passed to William's nephew Humphrey Fitzalan, 8th Earl of Arundel, who was only a six-year-old with no descendants.

William thus became the heir presumptive and, when Humphrey died three years later on 24 April 1438, he succeeded to the title.

Edward IV of England named him a Knight of the Garter in 1471, probably in honour of his support during the Wars of the Roses.