William MacArthur (British Army officer)

Lieutenant-General Sir William Porter MacArthur, KCB (11 March 1884 – 1964) was an Irish British Army officer and doctor. He served as Commandant of the Royal Army Medical College from 1935 to 1938, and Director General Army Medical Services from 1938 to 1941. His specialism as a doctor was tropical medicine and he served as President of the Royal Society of Tropical Medicine and Hygiene from 1959 to 1961.

MacArthur was born on 11 March 1884, in Belmont, Belfast. He studied medicine at Queen's University Belfast. He graduated in 1908 and began his year of house officer rotations at the Royal Victoria Hospital.

In 1908, MacArthur was commissioned into the Royal Army Medical Corps, British Army. In 1911, he completed his Doctor of Medicine (MD) degree and he was posted to Mauritius as a specialist sanitary officer. He was promoted to captain on 30 July 1912. He became a Fellow of the Royal College of Physicians of Ireland (FRCPI) in 1913. He returned to the United Kingdom with the outbreak of World War I in 1914. During the war he served at the School of Hygiene.