Lieutenant General Robert Harold Nimmo, was a senior Australian Army officer who served in World War I, in World War II, with the British Commonwealth Occupation Force in Japan, as general officer commanding (GOC) Northern Command in Australia, and finally as the chief military observer of the United Nations Military Observer Group in India and Pakistan from 1950 until his death in 1966. Raised on a sheep station in far north Queensland, Nimmo attended the Southport School in southern Queensland before entering the Royal Military College, Duntroon, in 1912. He was the senior cadet of his class, graduating early to participate in World War I. He served with the 5th Light Horse Regiment during the Gallipoli and Sinai and Palestine campaigns, reaching the rank of major. He was praised for his leadership as a light horse squadron commander and for his skills as the brigade major of the 1st Light Horse Brigade in the final stages of the war.

The Senior Officers' School was a British military establishment established in 1916 by Brigadier-General R.J. Kentish for the training of Commonwealth senior officers of all services in inter-service cooperation. It was established as part of a wider attempt by the British Army to create a coherent training plan for its officers.