Arthur Henry Machell Cox (11 November 1870 – 1968) was an English ornithologist. Cox was born in Hazelwood, Derbyshire, England, on 11 November 1870. He was educated at Trinity College, Cambridge, before working as a teacher and then headmaster at various schools in Devon. He contributed to ornithological research in Devon, was a founding member of the Devon Bird Watching and Preservation Society in 1928 and, from its inception in 1931, a member of the . At one time he lived in Yelverton. He died in 1968, by which time he had moved to Somerset.