Relationships with peers and teachers are keys for children's psychosocial development. However, it is unclear whether this also applies for high-ability children. This study adds to the literature by longitudinally examining the role of interpersonal relationships in the educational context for high- and average-ability students. In this study, we examined whether high- and average-ability students differ in terms of peer acceptance, teacher conflict, and school well-being. Further, we studied the potential bi-directional effects between school well-being, teacher conflict, and peer acceptance in late childhood and examined whether the relations between these concepts differ between high- and average-ability students. The total sample consisted of 3,101 Belgian students (49.9% boys, Mage = 9.76 years), with 348 high-ability and 2,753 average-ability students. Cognitive ability was assessed in Grade 3 with two cognitive ability tests (for crystallized intelligence and fluid intelligence, respectively). The students were followed for three years (Grades 4, 5, and 6), and each year their current teacher filled out questionnaires regarding teacher-child conflict, peer acceptance, and school well-being. High-ability students showed lower teacher conflict, higher peer acceptance, and better school well-being than average-ability students. Cross-lagged analyses showed that peer acceptance consistently predicted school well-being over time, while Grade 4 school well-being impacted Grade 5 teacher conflict. Also, better peer acceptance in Grade 5 predicted lower teacher-student conflict in Grade 6. Multigroup analyses revealed similar associations for both groups. Our results show that high-ability students in general display more positive school-based social relationships and school well-being than average-ability students. We found no differences in the links between these variables for both groups (i.e., high-ability students and average-ability students).