Background: Understanding the correlates of young children's social emotional development is important to optimally support children's long-term success. Objective: This study examined the associations among dimensions of parent-teacher cocaring relationships, infants' and toddlers' social emotional adjustment, and parent-child closeness and conflict. Method: Our sample consisted of 90 families utilizing full-time, center-based childcare for their 12-36 month old child, about a fourth of whom received subsidized childcare. Parents completed a set of questionnaires about themselves, their cocaring relationship with a particular classroom teacher, their relationship with their child, and the child's social emotional functioning. Results: After controlling for children's age, parents' race and education, and childcare subsidy receipt, HLM analyses revealed significant associations. After accounting for parent-child relationship quality, parents' perceptions of cocaring endorsement were positively associated with child competence, and perceptions of cocaring undermining were positively associated with children's dysregulation. In addition, reported cocaring endorsement demonstrated a marginal negative association with parent-child conflict. Parent-child conflict was significantly associated with all forms of children's social emotional functioning, while parent-child closeness was only associated with child competence. Conclusions: Findings highlight the importance of adult-relationships in children's early social emotional development, with an emphasis on the cocaring relationship as a bridge between home and child care contexts, and the utility of the cocaring framework as a guide for examination of and reflection on the processes underlying parent-teacher relationships.