Background: Previous studies have found that post-institutionalized (PI) children are particularly susceptible to attention problems and perform poorly on executive functioning (EF) lab tasks. Methods: Parent ratings of EF were examined in 288 school-age and 130 preschool-age children adopted from psychosocially depriving Russian institutions that provided adequate physical resources but not one-on-one interactions with a consistent set of responsive caregivers. Results: Results revealed a step-like association between age at adoption and EF deficits; school-age children adopted after 18 months of age had greater EF difficulties than younger-adopted children and the never-institutionalized normative sample. The onset of adolescence was associated with a greater increase in EF deficits for children adopted after 18 months than for younger-adopted children. Preschool-age children were not found to have greater EF difficulties than the normative sample. Conclusions: These findings suggest that prolonged early psychosocial deprivation may increase children's risk of EF deficits and that the developmental stresses of adolescence may be particularly challenging for older-adopted PI children.