Selective education research has demonstrated that students are aware of the low status of being allocated to a low-ability school. Recent data in Guyana has shown that low-ability school attendance is associated with low rates of student attendance, retention, and graduation. This study aims to understand the effects of ability grouping on students by comparing the psychosocial well-being of students from different ability schools. Data was collected from a sample of 193 adolescents (70 males and 123 females) aged 13-18 from four secondary schools; representing the four school ability rankings. It was hypothesised that student psychosocial well-being would be significantly lower in low-ability schools compared to high-ability schools. Unexpectedly, the results indicated that the highest ability school had significantly lower psychosocial well-being than the other lower ability schools. The results may be potentially explained by the theory of Big-Fish-Little-Pond Effect, however confirmation in future research is warranted.