Lieutenant-Colonel Robert Beresford Seymour Sewell CIE FRS FLS FZS (5 March 1880 – 11 February 1964) was a British military doctor who served with the Indian Medical Service and served as a Surgeon Naturalist in the marine surveys, specializing on the taxonomy of copepods, and acted as an editor of The Fauna of British India, Including Ceylon and Burma 1933-1963. He married Dorothy Dean (died 1931) in 1914. They had two daughters, one who became a nurse and the other a scholar of English literature. He was a freemason, having been initiated in 1912 in the Lodge Concordia at Calcutta.