Deficits in social communication are fundamental behavioral outcomes in children and adolescents with Autism Spectrum Disorder (ASD), and are manifested in a lack of orientation to, and engagement with, communication signals, including speech. It is possible that communication difficulties arise from impairments in the connections between areas of the brain involved in speech and those that support the processing of social reward cues and emotion; disconnection between these regions could significantly impact the basic motivation to engage in social communication. This is an important area to understand, as speech is a critical communicative tool that is essential throughout the lifespan, and a lack of motivation to pursue social communication may aversely impact the development of other key social skills. However, little is known about how the social brain develops in children and adolescents with ASD. Thus, this project seeks to map out developmental changes in brain function, as well as the formation of critical connections between speech and reward regions of the brain, during late childhood and adolescence, in both individuals with ASD and those without. Using functional magnetic resonance imaging, we will examine brain function in 40 individuals (ages 7-18 years) with high functioning autism and 40 typically-developing individuals as they listen to both their mothers’ voices and strangers’ voices. As a mother’s voice is arguably the earliest and most critical vocal source in a child’s life, we predict that the brain’s reward systems will be more engaged when participants hear these sounds relative to when they hear strangers’ voices. We also predict that the development of these critical brain areas will differ between individuals with and without ASD. The results of this study have the potential to contribute to the identification of critical developmental time periods during which brain-based treatments of social impairments may be most helpful to individuals with ASD.