In Bangladesh, despite significant progress in access, equity and public examination success, poor student performance in mathematics in secondary schools has become a major concern. An extensive review of research has shown that teachers account to a large extent for student learning and achievement gains. Although educational research has emphasised the importance of evaluating teacher effectiveness for improving students' achievement, few studies have measured teacher effect on students' achievement in Bangladesh and similar country-contexts. Thus, the purpose of the study was to investigate the value-added effect of mathematics teachers in secondary schools in Dhaka, Bangladesh. A cross-sectional cohort research design was employed, using a purposive sampling (N= 380) of all schools within the Dhaka Metropolitan City (DMC), extracted from the 5,867 schools under the jurisdiction of the Board of Intermediate and Secondary Education (BISE), Dhaka. Secondary source data for Junior Secondary Certificate (2010) and the Secondary School Certificate (2013) were obtained from BISE Dhaka and analysed using Education Value-Added Assessment System (EVAAS). The 380 schools of the DMC were ranked according to the calculated value-added score, and the top twenty schools identified. As the first study to evaluate secondary mathematics teachers' direct effect on students' mathematics learning in Bangladesh, it contributes important insights about teacher effect that can be used to inform the development of evidence-based policy and practice for improving teaching quality in Bangladesh.