The aim of the present study was to compare students academic achievement through Urdu and English language as a medium of instruction at secondary school level. It was descriptive research base on survey design. Data was collected from 1416 students of 10th class who were selected by applying a simple random sampling technique via a self-developed questionnaire. The collected data was arranged and coded. The coded data was entered into computer and analyzed by applying inferential statistics with the help of SPSS (version 20) software. The result shows that the students who were being taught via Urdu language as a medium of instruction, their learning level was high because the majority of them performed excellent in the exam while the students who were being taught via English language as a medium of instruction, their learning level was moderate because the majority of them performed good in the exam. Moreover, the students who were studying in the secondary schools who obeyed educational policy and changed the medium of instruction from Urdu language to English language. When they were teaching via Urdu language before the arrival of educational policy, theirs students academic achievement level was high and the majority of the students were performing excellent, as they followed educational policy and changed the medium of instruction from Urdu language to English language, the learning level of their students decreased because the majority of them performed just good in the exam.
Key words: Students academic achievement, Medium of Instruction (Urdu & English), Secondary School