William Duff

William Duff may refer to:

• William Duff, 1st Earl Fife (1696–1763), Scottish peer
• William Duff (cricketer) (1890–1953), South African soldier and cricketer
• William Duff (writer) (1732–1815), historically influential Scottish writer on genius and creativity
• William E. Duff, author
• William J. Duff (1856–1922), American football player
• William Duff (Canadian politician) (1872–1953), merchant and politician in Nova Scotia, Canada
• William Duff (Newfoundland politician) (1842–1913), Newfoundland merchant and politician
• William Duff (dentist) (born 1962), Scottish dentist
• Willie Duff (1935–2004), Scottish footballer
• William Duff (Arabist) (1922–2014) Scottish Arabist and banker, known to be one of the architects of modern Dubai
• Bill Duff (born 1974), NFL footballer