<p>Puberty demarcates the start of adolescence, a critical period of marked changes in motivated behavior (e.g., approach, avoidance) and socio-affective processing supported by development of the mesocorticolimbic circuitry—prefrontal cortex (PFC), amygdala, and nucleus accumbens (NAcc). Puberty-related increases in psychiatric risk have been linked to alterations in mesocorticolimbic circuitry function and sensitivity to rewards and punishments. Yet, how puberty influences the development of mesocorticolimbic circuitry supporting motivational traits remains unclear. We examined resting-state functional connectivity (RSFC) in 126 adolescents, studied longitudinally (216 total scans over 2 years), assessed reward/punishment sensitivity via questionnaires, and collected multimodal measures of puberty. As hypothesized, fronto-striatal RSFC was associated with reward sensitivity, but both fronto-striatal and fronto-amygdala RSFC were linked to punishment sensitivity. Puberty moderated several associations in males but not females: weaker fronto-striatal RSFC related to higher reward sensitivity in males more advanced in pubertal maturation. Further, whereas in early puberty stages stronger fronto-striatal RSFC related to higher punishment sensitivity in males, by late puberty stages, stronger fronto-amygdala RSFC was related to higher punishment sensitivity. Testosterone levels moderated the association between anterior ventromedial PFC - NAcc RSFC and reward sensitivity such that weaker RSFC related to higher reward sensitivity in males with lower testosterone levels than expected for their age and pubertal status. These data support sex-specific puberty effects on the relationship between mesocorticolimbic circuitry connectivity and reward/punishment sensitivity. Future research is needed to determine how these findings represent markers of risk for or resilience against psychiatric disorders.</p>