Inspector-General Belgrave Ninnis (1 September 1837 – 18 June 1922) was a Royal Navy surgeon, surveyor, Arctic explorer, and leading Freemason, from London. He graduated as a Doctor of Medicine from the University of St Andrews in 1861, and the same year entered the navy as an Assistant Surgeon. From 1864 to 1866, Ninnis served as part of a surveying expedition to the Northern Territory of South Australia, helping to chart the area to the west of the Adelaide River and returning biological specimens to Adelaide for study. In 1867 Ninnis was appointed to Greenwich Hospital (later the Royal Naval College, Greenwich), and in 1875 he joined the British Arctic Expedition under Captain Sir George Nares, serving as Staff-Surgeon on HMS "Discovery". When disease spread among the expedition's dogs, Ninnis was charged with investigating the cause; his findings later formed the basis of a published work. At the conclusion of the expedition in 1876 he received the Arctic Medal for his service, and was promoted to Fleet-Surgeon.