John Francis Campbell (Scottish Gaelic: Iain Frangan Caimbeul), also known as Young John of Islay (Scottish Gaelic: Iain Òg Ìle), was a Scottish author and scholar who specialised in Celtic studies. He was an authority on Celtic folklore and of the Gaelic peoples. He also invented a sunshine recorder that bears his name as the Campbell-Stokes recorder. He was heir to the island of Islay, until his father was forced to sell his estate in 1847.
With the assistance of contemporary scholars, such as Hector MacLean, Hector Urquhart, John Dewar and Alexander Carmichael, Campbell amassed a vast collection of original manuscripts related to Gaelic language and literature, which was later published as Popular Tales of the West Highlands (1860 - 62).