Arthur Henry Machell Cox (11 November 1870 - 1947) 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 Cornwall Bird Watching and Preservation Society.
At one time he lived in Yelverton.He died in 1947, by which time he had moved to Somerset.