John Barclay may refer to:

• John Barclay, London commercial trumpet player.
• John Barclay (1582–1621), a Scottish satirist and Latin poet.
• John Barclay (1734–1798), a Scottish divine.
• John Barclay (1758–1826), anatomist.
• John Barclay, a former Mayor of Philadelphia.
• John Barclay, survivor of the shipwreck of HMS Birkenhead in 1852.
• John Barclay (born 1954), cricketer.
• John Barclay (1795-1826), Canadian Church of Scotland clergyman;.