Adolescence ushers in dramatic social and affective changes and increased vulnerability for affective disorders. Yet, little is known about the effects of pubertal maturation on neural systems of social threat processing. We examined adolescents' brain function to social stimuli in relation to pubertal maturation, depressive symptoms, and real-world subjective negative affect. Compared with pre/early adolescents, mid/late adolescents exhibited less amygdala reactivity to emotionally neutral faces relative to non-face stimuli; less ventrolateral prefrontal cortex (VLPFC) reactivity to fearful faces relative to non-face stimuli, neutral faces, or angry faces; and more VLPFC reactivity to angry relative to neutral faces. Amygdala and VLPFC reactivity were correlated with negative affect and depressive symptoms. Threat-processing changes during puberty may facilitate changes in social behavior and negative affect.