John Campbell may refer to many different people:

• John Campbell, 1st Earl of Loudoun
• John Campbell, 2nd Duke of Argyll (1680–1743)
• John Campbell of Cawdor — minor British politician (1695—1777)
• John Campbell, 4th Earl of Loudoun (1705–1782)
• John Campbell, 5th Duke of Argyll (1723–1806)
• John Campbell — Kentucky state senator and founder of Louisville, Kentucky.
• John Campbell — US House Rep from Maryland (1765–1828)
• John Campbell, 1st Baron Campbell of St Andrews — Lord Chancellor of England (1779–1861)
• John Campbell — US House Rep from South Carolina (1795–1845)
• John Hull Campbell — US House Rep from Maryland (1800–1868)
• Sir John Logan Campbell, a prominent figure in the history of Auckland, New Zealand
• John Campbell, 9th Duke of Argyll — 9th Duke of Argyll (1845–1914)
• John Goulder Campbell — US House delegate from Arizona (1827–1903)
• John Edward Campbell — mathematician credited for the Campbell-Hausdorff formula (1862 – 1924)
• John W. Campbell — Science Fiction Author/Editor (1910–1971)
• John Campbell — Canadian Harness racing Driver (1955–Present)
• John Campbell (Canadian politician) , a Canadian Member of Parliament
• John Campbell — State Senator from California [1]
• John Campbell — Australian snooker player
• John Campbell — thoroughbred horse trainer
• John Campbell — Philosopher
• John Campbell — New Zealand television personality
• John Campbell — Bassist for Lamb of God
• John Campbell — Founder of what became Coutts bank