The POA was originally developed for small riders in need of a mount larger than a small pony, but not the size of a full-fledged horse. The breed standard originally had the height requirement between 11 and 13 hands (44 to 52 inches (112 to 132 cm)). However, since that time the height range has been changed to 11.2-14.0 hands (46 to 56 inches (117 to 142 cm)).

The head has large, expressive eyes with a small, refined, and sometimes has a "dished" face similar to an Arabian. The body is more like a stock horse, with plenty of muscling like a Quarter Horse, with a broad chest, round belly, sloping shoulders, and powerful hindquarters. The pony should have free-flowing movement, and the tail is never carried high. Today's POAs have the desirable movement of a forward-moving Quarter or Appaloosa horse. Troping and "peanut rolling" are discouraged. A level head set, smooth, slow movement and true gaits are desired.

The coloring of the pony must be the markings of an Appaloosa, and visible from a distance of 40 feet (12 m). This includes the spotted coat in any Appaloosa pattern and the white sclera, mottled skin around the eye, muzzle, and genitals, as well as striped hooves.