<p>Small schools have been increasing worldwide, yet research on school size has largely focused on cognitive outcomes, with limited attention to non-cognitive development, particularly social competence. Moreover, existing studies tend to highlight the advantages of small schools—such as close relationships and a strong sense of belonging—making generalization difficult given cross-national and contextual differences. This study examines social competence among students in small rural elementary and middle schools in Korea, where physical and social constraints are pronounced, using a mixed-methods approach. The results show that students in small elementary schools demonstrate higher levels of initiative, cooperation, and empathy, alongside lower levels of withdrawal and asocial behavior. In contrast, students in small middle schools exhibit decreased initiative and increased withdrawal and asocial tendencies. These findings reveal the duality of small rural schools: while relational intimacy functions as a developmental strength, limited relational diversity and restricted activity scale may hinder social competence as students' progress to higher school levels. Based on these results, the study suggests institutionalizing inter-school collaborative curricula, expanding social competence programs, and strengthening systemic support for small rural schools.</p>