William Milligan (disambiguation)

William Milligan may refer to:

• William Milligan, 19th-century Scottish theologian
• William Lane Milligan, 19th-century British military surgeon
• William Rankine Milligan, Lord Milligan, 20th-century Scottish politician and judge
• Billy Milligan, 20th-century American multiple personality
• Billy Milligan (baseball), 20th-century American baseball player