A ball python's head is flat on top, with no brows above its round eyes. It has a square, boxy snout, and heavy jaw muscles that make the sides of its head, behind the eyes, bulge outwards. It can securely hold prey with the 100-150 sharp teeth that curve towards the back of its mouth. Its neck is narrower than its head, but its stout trunk region can easily have a diameter of more than twice the width of its head. Its short tail tapers to a blunt end.
Females are larger, on average.
Alternating black and pale stripes along its face partly mask its dark eyes. Many of the lobed spots contain small dark spots. Some individuals have light or dark, broken or solid stripes along the spine. Young animals' spots are often yellow or golden, and darken as they age. A rare genetic piebald form, with patches of pure white, is found in the wild in Ghana and Togo, and breeders are using several imported animals to produce a captive-bred piebald line.