Boarding schools can provide quality secondary education for Aboriginal students from remote Aboriginal Australian communities. However, transition into boarding school is commonly challenging for Aboriginal students as they need to negotiate unfamiliar cultural, social and learning environments whilst being separated from family and community support. Accordingly, it is critical for boarding schools to provide programs that enhance the social and emotional skills needed to meet the challenges. This study evaluated a 10-session social and emotional learning (SEL) program for Aboriginal boarders and identified contextual factors influencing its effectiveness. The study combined a pre-post quantitative evaluation using diverse social and emotional wellbeing measures with 28 students between 13-15 years (10 female, 11 male, 7 unidentified) and qualitative post focus groups with 10 students and episodic interviews with four staff delivering the program. Students' social and emotional skills significantly improved. The qualitative findings revealed improvements in students seeking and giving help, working in groups, managing conflict, being assertive and discussing cultural issues. The focus groups and interviews also identified program elements that worked best and that need improvement. Secure relationships with staff delivering the program and participation in single sex groups stood out as critical enablers. The findings lend evidence to the critical importance of collaborative design, provision and evaluation of SEL programs with Aboriginal peoples.