This paper explores levels of achievement amongst boys who attended a selective school in Birmingham, UK through consideration of their attainment, social background and ethnicity. It seeks to answer three main questions. Firstly, to what extent does academic attainment vary between students from different socio-economic groups and ethnic backgrounds? Secondly, what are the possible reasons for these variations? Thirdly, what can selective schools do to close the gaps in attainment between these groups? The research study sought to determine whether different groups of boys in the case study school experienced social mobility, or social reproduction, as a consequence of the education they received. Using quantitative data of student attainment (n = 625), combined with information on their residential location, areas of comparatively low achievement across the city of Birmingham were mapped. Spatial data for levels of deprivation and ethnicity were also considered. The resulting map identifies areas of high vulnerability (HV) to poor performance, specifically by identifying the postcodes of neighbourhoods containing students who are most likely to underachieve. Qualitative data was gathered amongst students (n = 121) who were embarking on their General Certificate of Secondary Education (GCSE) studies. All were asked to identify factors that might affect their academic performance. These findings were then cross-referenced with the postcode study to help analyse possible reasons for underachievement. The main finding of this research was that the study school experiences a distance-decay effect in relation to examination success. Boys from Black and Minority Ethnic (BME) groups generally performed worse than White British (WB) boys, while students from deprived areas of the city were also less likely to succeed. Students from poorer communities tend to live in environments of relatively low aspiration, although one inner city area was identified as anomalous with regard to the achievements of its students. We conclude that social reproduction, rather than social mobility, is occurring within the case study school and suggest a range of initiatives to raise the levels of achievement of those who are most socially disadvantaged.