The South Devon is a British breed of large beef cattle. It originated in the counties of Devon and Cornwall in south-west England, and is mentioned from the eighteenth century. It was a dual-purpose breed, kept both for its milk and for beef. Since 1972 selection has been for beef only.

The Devon is a traditional British breed of beef cattle. It originated in, and is named for, the county of Devon in the West Country of England. It is a deep rich red in colour, and so may be known as the Devon Ruby or Red Ruby; it may also be called the North Devon to distinguish it from the South Devon.