Music is a complex communication system that takes children many years to master. We first consider musical development as it occurs in a social context, beginning with interactions between parents and infants. We then examine how children become enculturated listeners through everyday experiences, developing brain circuits specialized for the pitch, rhythmic, and emotional structures of their culture’s music. We review the development of singing production, from infants’ initial cooing to the high degree of sensorimotor coordination achieved by accurate singers. Last, we consider the effects of formal musical training on musical development as well as on other cognitive domains such as language and mathematics. Across these domains, there is evidence for some very early-developing, perhaps innate, abilities. At the same time, developmental trajectories are protracted, with adult levels not achieved for many years. Finally, there is much evidence that particular musical experience and formal training have large effects on musical outcome.Keywordsdevelopment, pitch, scales, consonance and dissonance, harmony, tonality, rhythm, meter, entrainment, enculturation