The ear is the organ of hearing. It is the organ of balance in mammals. In mammals, the ear is usually described as having three parts - the outer ear, the middle ear and the inner ear. The outer ear is composed of auricle and auditory canal. Since the outer ear is the only visible part of the ear in most animals, the term "ear" usually refers only to the outer part. The middle ear includes the tympanic cavity and three small bones. The inner ear is located in a labyrinth of bones and contains structures that are essential for several senses: semicircular tubes that are able to maintain balance and eye movement when moving; saccules and saccules that are able to maintain balance when stationary; and cochlea, which are able to be heard. Vertebrate ears are symmetrical on both sides of the head, which helps to locate the sound.

The ear develops from the first pharyngeal pouch and six small swells that develop in the early embryo, called ear spots, which originate in the ectoderm.

Ears can be affected by diseases, including infections and trauma. Ear diseases can cause hearing loss, tinnitus, and balance disorders (such as vertigo), although many of these diseases can also be affected by damage to brain or ear neural pathways.

For thousands of years, earrings and other jewelry from various cultures have been decorated, and ears have been surgically and aesthetically modified.