Hearing loss in children has multiple aetiologies, making diagnosis based on clinical signs and symptoms challenging. Hearing loss at a young age will affect a child’s cognitive and linguistic development, resulting in loss of quality of life and possible behavioural and social problems. It is important to screen before the end of the neonatal period, 1 month of age, as well as a follow up at 3 months, due to multiple progressive hearing loss causes. Congenital, delayed onset or acquired hearing loss in children is classified into timing of onset of symptoms. Genetic, non-syndromic, syndromic, and infectious causes are the most common aetiologies. Further characterization of hearing loss based on the mechanism of the auditory system involved yields conductive, sensorineural, and mixed hearing loss. The organisation of different sound frequencies in the auditory cortex ends at 2 years of age and indicates an important window period for intervention. The evidence of benefit from early application of hearing aids and cochlear implants supports the argument to treat and rehabilitate children early.