William Lancaster may refer to:
William de Lancaster I, or William Fitz Gilbert, was a nobleman of the twelfth century in Northwest England William Lancaster (Queen's) (1650–1717), English academic administrator and clergyman William Lancaster (anthropologist) (1938–2022), British social anthropologist studying various Arab tribes and communities William Lancaster (cricketer) (1873–1938), English cricketer William Lancaster (politician) (1841–1929), English politician and benefactor William H. Lancaster (1931–2000), member of the California State Assembly William Edward Lancaster (1909–2003), chief executive of the Royal Zoological Society of South Australia Willie Lancaster, Scottish footballer Bill Lancaster (1947–1997), American screenwriter Bill Lancaster (aviator) (1898–1933), British aviator