<![CDATA[Background: Social-emotional development is a fundamental aspect of early childhood education, supporting children's self-regulation, interpersonal relationships, and participation in learning and play activities. Changes in family caregiving arrangements following parental divorce may influence the social contexts in which these developmental competencies are expressed and supported. Objective: This study explored self-regulation and prosocial behavior in a five-year-old child receiving primary care from a grandparent following parental divorce, with particular attention to their implications for early childhood social-emotional development and educational support. Methods: A qualitative single-case study was conducted in June 2026 in Jember, Indonesia. Data were collected through naturalistic observation, semi-structured interviews with the child's grandmother and a neighboring informant, and supporting documentation. Data analysis involved data reduction, data display, and conclusion verification, with trustworthiness strengthened through source and technique triangulation and member checking. Results: The child demonstrated emerging self-regulation through responsibility and adherence to familiar household routines, although difficulties remained in turn-taking, frustration tolerance, and emotional regulation during social interactions. Prosocial behavior was more evident in close family relationships, particularly through empathy and helping behaviors, while sharing, sustained cooperation, and positive peer interactions were less consistent. These findings illustrate the context-dependent expression of social-emotional competencies in early childhood. Conclusion: The study highlights the importance of consistent developmental support and responsive caregiving practices in fostering young children's self-regulation and prosocial behavior. Collaboration between family caregivers and early childhood educators may provide opportunities to reinforce emotional regulation, sharing, and cooperative play across home and educational environments. However, findings from this single case do not establish causal effects of parental divorce or grandparent care and should not be generalized beyond the study context.]]>
