John Johnstone

John Johnstone (1768–1836) was a British physician and biographer.

Life John Johnstone was born to James Johnstone (1730?–1802) MD and his wife Hannah Crane. Among his brothers were Edward Johnstone and James Johnstone (1753–1783).

Johnstone became a fellow of the Royal College of Physicians of London in 1805, and a fellow of the Royal Society in 1815. A Reply to Dr. James Carmichael Smyth, containing remarks on his "Letter to Mr. Wilberforce", London, 1805. Presidential Address at the Second Anniversary of the Provincial Medical and Surgical Association at Birmingham, 1834. Address at the Birmingham School of Medicine on 6 Oct. 1834. These two last were published with the Harveian Oration.

Family Johnstone married Anna Delicia Curtis, daughter of Captain George Curtis, and niece of Sir William Curtis, 1st Baronet, on 26 December 1809. They had two daughters, Anna Delicia (born 1811), who married Walter Farquhar Hook, and Agnes Mary (born 1814), who married the Rev. Henry Clarke, son of Sir William Clarke, 1st Baronet (1762–1808).