This study attempted to explore the effects of social class on educational achievement in two private Advanced-level (A-level) schools in Karachi. The schools that are generally known as ‘A-level schools’ in Pakistan are the ones that offer Cambridge International Examination (CIE) curriculum for A-level examination. By using semi-structured interviews and observations, the researcher sought to highlight how social class played out in different levels of achievement within the A-level stream, whereby the themes of grades/university admissions, lived experience of social class, advantages and disadvantages of belonging to a particular social class and teacher interaction were investigated using qualitative research methodology. This helped to point out and highlight how crucial social class is in terms of its effects on student achievement and how varied its effect could be. The Pakistani literature focusing on class distinctions and education generally focus on three different streams of schools i.e. madrassa, government and private. This research focuses on English medium stream and particularly the A-level schools, which are supposedly catering the higher social class. The research findings indicate a case of ‘class within class’ whereby relative deprivation exists within this stream. The research findings indicate that relative poverty disadvantages students in a number of ways, such as low availability of resources and to overcome that, students work part-time. This then has effect on their performance and career ambitions. Therefore, the study recommends that in any overhauling of the system of education within the country, care must be taken to address the fundamental class barriers that create fissures in our educational system and educational experience of many of our students. This study can be taken to be a first step to bringing about meaningful educational change in A-level schools in Karachi where barriers to learning for the lower socioeconomic classes are addressed.