This study examined cognitive-affective strategies as predictors of hypothalamic-pituitary-adrenal (HPA) axis responses to a social-evaluative stressor in adolescence as compared to late childhood as a function of early life experiences. Participants included 159 children (9-10 years) and adolescents (15-16 years) divided into two groups based on early care experiences: non-adopted youth raised in their birth families (n = 81) and post-institutionalized youth internationally adopted from orphanage care (n = 78). Youth completed a version of the Trier Social Stress Test modified for use with children and reported on their trait emotion regulation and coping strategies. Children reported more use of suppression and disengagement than adolescents, while adolescents reported more engagement coping strategies. Non-adopted and post-institutionalized youth did not differ in reported strategies. Cognitive reappraisal predicted higher cortisol reactivity in non-adopted children and adolescents, and was not associated with reactivity in the post-institutionalized group. This study has implications for efforts aimed at promoting self-regulation and adaptive stress responses during the transition to adolescence for both typically developing children and children who experienced adverse early care.