John Gray 15th Lord Gray 1798 – 1867, succeeded to his title 1842, Deputy Lieutenant for Perth, Magistrate at Forfar, Member of the House of Lords, was a Vice President of the London Homeopathic Hospital, Member of the Medical Committee of the British Homeopathic Association,
John Gray signed the Petition supporting homeopath Alfred Crosby Pope, when in 1851, Alfred Crosby Pope was refused his MD degree from his Alma Mater, the University of Edinburgh, in 1857 due to his conversion to homeopathy,
The family seat was Kinfauns Castle in Perth, built by the 14th Earl, it is now a hotel.
John Gray, 15th Gray was born on 12 May 1798. He was the son of Francis Gray, 14th Lord Gray and Mary Anne Johnston. He married Mary Anne Ainslie, daughter of Colonel Charles Philip Ainslie, on 23 May 1833. He died on 31 January 1867 at age 68 at Paris, France (at 18 Champs Elysees), without issue. John Gray, 15th Gray succeeded to the title of 15th Lord Gray on 20 August 1842.