This application aims to provide better understandings of the inner ear, in particular the vestibular system. The knowledge is categorized into the basic anatomy and physiology of the inner ear, emphasizing on the organs which associate with the vestibulo-ocular reflex (VOR). Several standard otolaryngology and neurotology resources were selected, referenced and applied by using pictorial illustrations in order to facilitate the better comprehension of the peripheral vestibular system and the VOR.