Lieutenant-Colonel George John Carnegie, 9th Earl of Northesk DL (1843 – 1891) was a British nobleman and soldier.
He was born the son of William Carnegie, 8th Earl of Northesk and Georgiana Maria Elliot on 1 December 1843. He died on 9 September 1891 at age 47.
Lord Rosehill, as he then was, was commissioned into the 1st Dragoons in 1862, but transferred to the Scots Fusilier Guards as a Lieutenant later the same year. He was promoted Captain in 1866 and Lieutenant-Colonel in 1873. He retired in 1874.
He married Elizabeth Georgina Frances Elliot, daughter of Admiral Sir George Elliot and Hersey Susan Sydney Wauchope, on 28 February 1865 and had four children.
He rebuilt Longwood House, Hampshire, his main home. The architect was George Devey.