The Cervidae first appear as fossils in the early Miocene of Asia, where they expanded into a wide variety of niches (and were thus able to dominate over the bovids which arrived later). During the Miocene, members of this family migrated to North America. After expanding in the Nearctic region, deer crossed to South America during the Pleistocene, when the Panama land bridge formed.

Antlers are the defining characteristic of this family: all but one species (Hydropotes inermis) possess these cranial appendages, and they are found in no other animal. Unlike the headgear of other Pecorans, antlers are composed entirely of bone and often have elaborate branching patterns. The antlers grow from an extension (the "pedicel") on the skull's frontal bone, joining to the skull in a suture known as a burr. The sutures holding the antlers to the deer's head decalcify on an annual basis (under hormonal control), causing the antlers to fall off (usually in the late fall or early winter in temperate species). After shedding, the antlers soon begin to regrow. During the growth period, the expanding bone is covered with a thin layer of fuzzy skin known as velvet, which helps protect the growing tissue. Because the entire antler is alive, growth is not limited to the base (as in horns) which results in branching patterns which are often species-specific. Unlike the horns of bovids, the regular shedding of antlers makes them a current marker of an animal's status: their size and shape are in direct correlation to age and dominance. In the vast majority of species, antlers are borne only by males - only in the reindeer, Rangifer tarandus, do females regularly grow antlers.

Males of a few species possess enlarged, tusk-like upper canines (Hydropotes, Muntiacus, Elaphodus). In other species the upper canines are either vestigial or absent. The dental formula is thus I 0/3, C 0-1/1, P 3/3, M 3/3 x 2 = 32-34. The molars are selenodont, and usually brachyodont. There are usually two lacrimal canals. Females usually have two pairs of mammae, and the young of most species are spotted. There is no gall bladder.