John Haynes
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