--- - |2 Abstract Ethnoracially diverse families living in poverty are vulnerable to stress, discrimination, and adversities that can be ‘toxic’ to parenting and to a wide range of psychosocial and academic outcomes in youth. Thus, there is high need to identify malleable protective and promotive factors that may lead to improved developmental trajectories and outcomes for at‐risk youth and families. In this study of 2,233 low‐income families with ethnoracially diverse children (49.5% girls; 42.5% European Americans, 38.4% African Americans, and 19.1% U.S. Latino/as), we tested a model positing that child‐rearing beliefs at 24 months and parenting practices at 36 months are precursors to the development of children’s self‐regulation at pre‐kindergarten, with self‐regulation as a mediating mechanism between parenting in toddlerhood and psychosocial and academic functioning at fifth grade. Results confirm that child‐rearing beliefs are precursors to parenting practices, and both parenting practices and self‐regulation are mediating mechanisms by which child‐rearing beliefs are linked to youths’ psychosocial and academic outcomes. The results have implications for early parent education and parenting interventions, including public health approaches that have the potential for positive impacts on vulnerable children, youth, and families. - Social Development, Volume 27, Issue 4, Page 891-909, November 2018.