Adam Nicolson, 5th Baron Carnock, FRSL, FSA (born 12 September 1957), is a British author who writes about English history, landscape and the sea.

He is noted for his books Sea Room (about the Shiant Isles, a group of uninhabited islands in the Hebrides); Power and Glory: the making of the King James Bible; Men of Honour (about Admiral Nelson and the Battle of Trafalgar); Earls of Paradise (an exploration of Arcadianism in 16th and 17th century England); The Smell of Summer Grass (describing his struggles with a small Sussex farm); and Sissinghurst: an Unfinished History (describing his attachment to his family home and his plans to transform the landscape there). In 2011 he published The Gentry: Stories of the English (about the last six centuries of gentry culture in England).