Adult musicians show superior neural sound discrimination when compared to nonmusicians. However, it is unclear whether these group differences reflect the effects of experience or preexisting neural enhancement in individuals who seek out musical training. Tracking how brain function matures over time in musically trained and nontrained children can shed light on this issue. Here, we review our recent longitudinal event‐related potential (ERP) studies that examine how formal musical training and less formal musical activities influence the maturation of brain responses related to sound discrimination and auditory attention. These studies found that musically trained school‐aged children and preschool‐aged children attending a musical playschool show more rapid maturation of neural sound discrimination than their control peers. Importantly, we found no evidence for pretraining group differences. In a related cross‐sectional study, we found ERP and behavioral evidence for improved executive functions and control over auditory novelty processing in musically trained school‐aged children and adolescents. Taken together, these studies provide evidence for the causal role of formal musical training and less formal musical activities in shaping the development of important neural auditory skills and suggest transfer effects with domain‐general implications.