Early prefrontal cortex damage has been associated with developmental deficits in social adaptation, moral behavior, and empathy that alter the maturation of social cognition and social emotions. The seminal case of Ackerly and Benton (1948) continues to provide the most striking clinical example of prefrontal-related neurodevelopmental impairments, with more recent case reports confirming and elaborating these influential observations. This study investigated the prefrontal hypothesis of moral decision making in healthy, typically developing children and adolescents (10-17 years of age) using functional magnetic resonance imaging (fMRI). Participants judged the actions in age-appropriate moral vignettes as right or wrong, and results were contrasted to a nonsocial/nonmoral baseline condition requiring similar right versus wrong judgments. Results confirmed a predominant cluster of activity in the most rostral-medial (frontal polar) prefrontal region across moral judgment conditions, along with left lateroposterior orbitofrontal/ventrolateral prefrontal, left temporoparietal junction, midline thalamus and globus pallidus, and bilateral inferior occipital clusters. Trials entailing ambiguous moral situations activated considerably more prefrontal and parietal regions than did routine moral situations, suggesting the need for more neurocognitive resources. While age regression analysis identified a few regions of greater or lesser activity with age, the frontal polar activations did not change with age. Findings confirm a significant role for anterior-medial prefrontal cortex in the typical development and maturation of moral decision making, consistent with clinical lesion case descriptions.