George William Balfour MD LLD FRSE (2 June 1823 – 9 August 1903) was a Scottish physician, known as a heart specialist.
Born at the manse of Sorn, Ayrshire, on 2 June 1823, he was sixth son and eighth of the thirteen children of Rev Lewis Balfour DD (1777-1860), by his wife Henrietta Scott, third daughter of George Smith, D.D., minister of Galston; James Balfour was a brother, Thomas Stevenson was a brother-in-law, and Robert Louis Stevenson was a nephew. After education at Colinton, he planned first to study veterinary science and settle in Australia; but entered the Medical School of Edinburgh. In 1845 he graduated M.D. at the University of St. Andrews, and was licensed by the Royal College of Surgeons of Edinburgh.
After acting as house surgeon to the Maternity Hospital of Edinburgh, Balfour in 1846 went to Vienna, where he studied under Joseph Škoda, Carl Ludwig Sigmund, and Wilhelm Fleischmann the homeopath. Balfour was a general practitioner in Midlothian from 1846 till 1857, when he removed to Edinburgh, and practised as a physician on becoming F.R.C.P. Edinburgh in 1861. In 1866 he was appointed physician to the Royal Hospital for Sick Children, and from 1867 he was physician to the Royal Infirmary, being appointed consulting physician in 1882, on the expiry of his term of office.
Balfour specialised in diseases of the heart and circulation, a leading figure of his time in the area with Sir William Tennant Gairdner in Glasgow, and Charles Hilton Fagge in London. He was librarian to the College of Physicians of Edinburgh from 1873 to 1882 and from 1887 to 1899. He was president of the college 1882-4, and was a member of the University Court of St. Andrews for many years. He received the honorary degree of LL.D. at Edinburgh in 1884, and at St. Andrews in 1896. He was appointed physician in ordinary to Queen Victoria in 1900 and honorary physician to King Edward VII in 1901.