BRAC initiated Computer Aided Learning (CAL) programme, the first ever in Bangladesh, to introduce ICT based materials in teaching-learning in 2004 Along with digital contents of Science, English and mathematics of secondary level, this programme provided basic ICT and content delivery training to the teachers of programme schools. A qualitative evaluation following the Realist Evaluation framework was designed to evaluate the programme mechanism, context and outcome. Data were collected from six secondary schools selected purposively. Findings showed that both teachers and students enjoyed the CAL materials and also believed that those materials had changed classroom scenario by improving learners’ attention and participation in classroom activities. However, significant difference was not observed between CAL and non-CAL classrooms. Teachers struggled to organise collaborative learning tasks such as group and pair works. Students also had limited participation in teaching-learning process. Irregular electricity supply sometimes hampered use of CAL materials. Furthermore, students had limited access to these materials. Bearing this context the recommendations were to focus more on teachers’ pedagogic improvement and to create more scopes for students’ self use of these materials.