Lieutenant General Henry John Coates, AC, MBE (28 December 1932 – 11 June 2018) was a senior officer in the Australian Army who served as Chief of the General Staff from 1990 to 1992.

After retiring from the army, he became an author and a visiting fellow at the Australian Defence Force Academy branch of the University of New South Wales, pursuing aspects of Australia's military history.

He served with the unit until 1958, when he was promoted to captain and reassigned as adjutant of the 10th Light Horse Regiment for a period of two years.

[5] Coates was appointed commandant of the Royal Military College, Duntroon in 1983[2] and head of the Defence Staff in Washington, D.C., in 1984;[2] he was appointed an Officer of the Order of Australia in 1987 in recognition of his service there.

These include: Coates was a visiting fellow in the School of Humanities and Social Sciences at Australian Defence Force Academy campus of the University of New South Wales (UNSW@ADFA).