Emerging adulthood (EA) is marked by a prolonged developmental transition to adulthood, dynamic personal and environmental circumstances, and unique patterns of vulnerability to psychological dysfunction. Neurodevelopment in childhood and adolescence has been studied extensively, but EA has not yet received its due attention from developmental cognitive neuroscience. The existing evidence shows that neurodevelopment continues throughout EA in support of emerging adult roles. The data suggest a frontolimbic fine-tuning model of brain development in EA that holds that adult functions are promoted through the strengthening of prefrontal regulation of limbic function and a newly emerging balance between prefrontal subregions involved in modulating approach and avoidance. Considering the overlap between these neurodevelopmental processes and the peak incidence of numerous psychological disorders in EA, it seems that individual differences in the dynamics of emerging adulthood neurodevelopment may not only underlie differences in functioning, but also risk for psychological disorder.