Adolescents in alternative care are at high risk of developmental outcomes. However, adolescence also offers avenues for positive changes and recovery from early adversities. To date, research has faced challenges in determining how adolescents’ psychosocial functioning changes during their time in care, and underlying mechanisms that contribute to resilience and wellbeing. Therefore, the question of “what works, for whom, and in what circumstances?” remains unanswered. The CAREFAL project draws on psychology, social anthropology, and public health to disentangle the developmental trajectories of adolescents in two alternative care settings (i.e., family foster care, residential care). This unique proposal aims to explore the differences across settings and how adolescents’ self-regulation interacts with the quality of their relationships with caregivers to promote positive outcomes. Additionally, CAREFAL aims at comparing the two cases of Spain and Portugal to optimize services and resources in each country. I will use a longitudinal, mixed-method, multi-informant, comparative approach to achieve the research objectives. The quantitative phase will involve a 6- month longitudinal study, incorporating data from caregivers, adolescents, and administrative records. This will be complemented by in-depth interviews with adolescents and caregivers. The research outputs will have: 1) scientific impact, as they will enhance our understanding of adolescent development across alternative care settings; 2) social impact, as they will equip families and professionals with evidence-based resources for improving adolescents’ self-regulation and caregiver-youth relationships; and 3) economic impact, as they will contribute to the specialization of alternative care and the efficient use of resources. By enhancing my expertise through conceptual, methodological, and communication training, I will be better equipped to showcase my abilities in both academic and non-academic markets.