John Haynes may refer to:

• John Haynes (draughtsman) (fl. 1730–1750), British draughtsman and engraver
• John Haynes (governor) (1594–1653/54), colonial governor of Massachusetts and Connecticut
• John Haynes (journalist) (1850–1917), Australian journalist and politician
• John Haynes Jr. (1937–2021), family physician, surgeon and community leader of Northwest Louisiana and Northeast Texas
• John Carmichael Haynes (1831–1888), Irish-born rancher, judge and public servant in British Columbia
• John Earl Haynes (born 1944), American historian
• John Henry Haynes (1849–1910), American traveller, archaeologist, and photographer
• John Randolph Haynes (1853–1937), California socialist
• John C. Haynes & Co., American maker of musical instruments (late 19th century)
• Johnny Haynes (1934–2005), English footballer

• John Haynes Holmes (1879–1964), American politician
• John Haines (disambiguation)
• John Hanes (disambiguation)