Research Findings: In this study, we examined self-regulatory skills, namely, effortful control and executive function, in Turkish preschoolers (N = 217) and their mediating roles in the associations between parenting and children's socioemotional competence. We also investigated the role of family socioeconomic status and maternal psychological well-being in these concurrent associations. Mother reports were used for maternal depressive symptoms, parenting behaviors, and children's effortful control. Individual assessment was utilized for executive function, and socioemotional competence was assessed via multiple methods (mother report, teacher report, and individual assessments). Structural equation modeling results showed that effortful control mediated the paths from power-assertion to children's socioemotional competence. The pathway extending from depressive symptoms to socioemotional competency was mediated by power-assertiveness and effortful control. Socioeconomic status was not associated with socioemotional competence through either parenting or self-regulatory constructs. Practice or Policy: The results revealed that even moderate levels of depressive feelings experienced by mothers presented a risk factor for early effortful control and socioemotional development in young children through increasing harsh child rearing. These findings suggest that, given its potential role in the development of early fundamental abilities, it is important to take precautions against adverse effects of even low levels of maternal depression.