William Hancock may refer to:

• William Augustus Hancock (1831–1902), American pioneer, surveyor, engineer, politician, and jurist
• William Hancock (priest), Anglican priest in Australia
• William Hancock (ophthalmologist) (1873–1910), English ophthalmologist and sportsman
• William Hancock Sr. (judge) (died 1762), commissioned Hancock House in Lower Alloways Creek Township, New Jersey
• William Hancock Jr. (judge) (died 1778), mortally wounded at the Hancock's Bridge massacre
• Billy Hancock (1946–2018), American singer, guitarist, and recording artist
• Keith Hancock (historian) (William Keith Hancock, 1898–1988), Australian historian
• William Hancock of Pendle Hall, Lower Higham, Padiham, Lancaster, father-in-law of Thomas Anderton (1611–1671)
• William Hancock (botanist) (1847–1914), commemorated by Cyathea hancockii
• William Hancock (brewer) of Hancocks Brewery in the South West of England, father of Frank, Froude and William Hancock
• William Hancock (rugby), England national rugby union player, Newport RFC, and Salford (RL), first capped 1955
• William J. Hancock, headmaster of Bastrop Academy, who commissioned Fowler House in 1852
• William John Hancock (1864–1931), telephone and X-ray pioneer in Western Australia
• William Hancock (architect), British architect, Gate Cinema
• Bill Hancock, a Canadian Alliance candidate in the 2000 Canadian federal election
• Bill Hancock (sports executive) (born 1950), American collegiate sports executive