Associations between early deprivation/neglect in the form of institutional care with the cortisol awakening response (CAR) were examined as a function of pubertal status among 12- and 13-year-old post-institutionalized youth. CARs indexed hypothalamic-pituitary-adrenocortical reactivity. Post-institutionalized youth were compared to youth adopted internationally from foster care (adoption control) and to nonadopted youth reared in families comparable in parental education and income to the adoptive families. Post-institutionalized youth exhibited a blunted CAR if they were at earlier but not if they were at later stages of puberty. Similarly, for both groups of internationally adopted youth combined, earlier but not later stages of puberty were associated with more blunted CARs at higher but not lower levels of parent-reported pre-adoption physical and social neglect.