John Hosack (baptised 1813 – 1887) was a Scottish lawyer and historical writer.
He was the third son of John R. Hosack of Glenaher, Dumfriesshire. He became a student of the Middle Temple in 1838, was called to the bar in 1841, and practised on the northern circuit and at the Liverpool sessions.
In 1875, though not a Q.C., Hosack was made a bencher of his inn, and in 1877 he became police magistrate at Clerkenwell. He died at his house in Finborough Road, West Brompton, on 3 November 1887, and was buried at Lytham in Lancashire.
- A Treatise on the Conflict of Laws of England and Scotland (only one part published), London, 1847.
- The Rights of British and Neutral Commerce, as affected by recent Royal Declarations and Orders in Council, London, 1854.
- Mary Queen of Scots and her Accusers, London, 1869; 2nd edit., 2 vols., Edinburgh, 1870–4; a defence of Mary Queen of Scots.
- On the Rise and Growth of the Law of Nations, … from the earliest times to the Treaty of Utrecht, London, 1882.
- Mary Stewart: a brief statement of the principal charges which have been brought against her, together with answers to the same, published after his death, Edinburgh, 1888.
- Metcalfe, Eric. "Hosack, John". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/13832. (Subscription or UK public library membership required.)
- Lee, Sidney, ed. (1891). "Hosack, John". Dictionary of National Biography. 27. London: Smith, Elder & Co.