This study investigated how high-ability Australian Aboriginal adolescents reasoned about sources of effort in their transition to secondary schools. High-ability Year 7 Aboriginal adolescents (n = 4) participated in interviews on three occasions: Term 1 Year 6 (primary); Term 1 Year 7 (secondary); and Term 4 Year 7 (post-transition). Parents (n = 5) and staff (n = 20) were interviewed on one or two occasions. The longitudinal, mixed-methods design included: longitudinal analysis of multiple case studies; discourse analysis; frequency tables; and content analysis of key themes pertaining to the research questions. Results indicated that effort investment was associated with class-average ability. High-ability Aboriginal students found difficulty transitioning to secondary school when placed in classes where the average-ability levels were higher than theirs, forcing upward comparisons, adversely impacting their academic self-concept. Schools should consider targeting academic skills and self-concept simultaneously and encouraging cooperation to enable a successful transition.