The Key Deer (Odocoileus virginianus clavium) is an endangered deer that lives only in the Florida Keys. It is a subspecies of the White-tailed Deer (O. virginianus).

This deer can be recognized by its characteristic size, smaller than all other White-tailed Deer. Adult males (known as bucks) usually weigh from 25 to 34 kg (55 to 75 pounds) and stand about 76 cm (30 inches) tall at the shoulder. Adult females (does) usually weigh between 20 to 29 kg (45 and 65 pounds) and have an average height of 66 cm (26 inches) at the shoulders. The deer is a reddish-brown to grey-brown in color. Antlers are grown by males and shed between February and March and regrown by June. The species otherwise generally resembles other white-tailed deer in appearance.