AbstractThe current research used reports among 350 Latinx young adults (60.3% male) between 18 and 21 years (Mage = 20.18, SD = 1.02). Using the cultural transmission model (Carlo & de Guzman, Handbook of U.S. Latino psychology. Sage Publications, Inc., 2009), the goal of the current study was to investigate the associations that sibling caregiving during adolescence, measured retrospectively, may have on ethnic identity resolution (EIR), and in turn, depressive symptoms, and responsibility among Latinx young adults. Path analysis results suggest that sibling caregiving was positively associated with EIR and responsibility. EIR was negatively associated with depressive symptoms and positively associated with responsibility. Both indirect effects via EIR were significant: sibling caregiving to depressive symptoms and responsibility. Our findings highlight that sibling caregiving affects young adult outcomes indirectly via ethnic identity development. The findings have important implications for practitioners and researchers to understand how ethnic identity may be related to young adult outcomes through a sibling‐focused lens. Family interventions that leverage sibling relationships can be incorporated to improve the well‐being of Latinx adolescents and young adults.