William Barlow may refer to:

• William Barlow (bishop of Chichester) (c. 1498–1568), English cleric
• William Barlow (bishop of Lincoln) (died 1613), Anglican priest and courtier, served as Bishop of Rochester and Bishop of Lincoln
• William Barlow (archdeacon of Salisbury) (died 1625), writer on magnetism, son of the Bishop of Chichester
• William Rudesind Barlow (1585–1656), recusant educationalist and rector of the English College in Douai
• William Barlow (dean of Peterborough) (1833–1908), Anglican priest

• Bill Barlow (1931–2020), Canadian politician, member of the Legislative Assembly of Ontario
• William K. Barlow (1936–2022), American politician, member of the Virginia House of Delegates

• William V. N. Barlow (1810–1909), American architect based in Albion, New York, namesake of the William V. N. Barlow House
• William Henry Barlow (1812–1902), English civil engineer
• William Barlow (pioneer) (1822–1904), Oregon pioneer
  • William Barlow House, Clackamas County, Oregon, former home of the pioneer
• William Barlow (vice-chancellor) (1834–1915), lawyer and Vice-Chancellor of the University of Adelaide
• William Barlow (geologist) (1845–1934), English geologist
• Billy Barlow (1870–1963), Canadian ice hockey player