Schools in Pakistan which follow the National Curriculum designed by Ministry of Education, register their secondary level students (grade IX and X) with certain examining bodies that assess these students through standardized tests. Aga Khan University Examination board (AKU-EB) is one of those examining bodies that enrol and assess secondary level students under either ‘Science’ or ‘General’ group. My academic and professional experiences reveal that teachers and school management of private schools are concerned about low academic performance of general group students in mathematics examinations. As a result, they put in efforts to improve students’ performance through arranging tests and remedial classes; however, most of these students do not take interest in mathematics and are unable to cope well in mathematics tests and examinations. This study is aimed to explore how various factors (such as familial, teaching learning processes at school and teachers’ beliefs about students’ ability) affect general group students’ performance in mathematics at secondary level. In order to achieve this purpose, a qualitative approach was adopted and data was collected through focused group discussions, classroom observations, semi structured interviews and analysis of documentary evidences (National Curriculum of Mathematics, AKU-EB final examination papers etc). Research participants included a school principal, two mathematics teachers, twelve general group students of a private school and two mathematics subject specialists of AKU-EB. The study revealed that mathematics teaching and learning practices in the school are inconsistent with the assessment criteria designed by AKU-EB which hinder students to prepare according to the expectation of AKU-EB. The study also revealed that teachers’ teaching practices are influenced primarily by certain beliefs which teachers possess about mathematics, its teaching and learning and students’ ability in mathematics. Moreover, teachers’ beliefs about students’ ability seem to have generated mainly from a placement criterion levied in the school for secondary level students. The study also explored other key factors affecting students’ performance that include students’ beliefs about mathematics teaching and learning, linguistic issues with mathematics teachers and parental involvement. This study opens a ground for more in-depth research studies about teachers’ and school management’s beliefs and practices related to general group context in Pakistan.