This qualitative study focused on four secondary school physics teachers in Bangladesh using semi-structured interviews and observations to explore their understanding about the relationship between practical work and developing students’ conceptual knowledge of physics. Recent studies indicate that practical work helps secondary science students easily and effectively learn the concepts and theories of physics. However, the secondary school physics teachers in Bangladesh in this study did not provide students with practical work during classroom teaching. Rather, they provided practical work in separate practical classes. Although the teachers believed that practical work made their teaching and also students’ learning easier and effective, they did not offer frequent practical demonstrations in teaching the contents of physics. The major findings of the study include that teachers used mostly transmissive pedagogy to assist students to understand physics concepts and theories. Even though there are clear and specific instructions for the teachers to do demonstrations in the secondary physics curriculum, there were constraints on teachers and on students trying to conduct practical work. Constraints included: a lack of sufficient equipment. Teachers and students in non-government schools faced comparatively more difficulties than those in government schools. Low teacher/student ratios and no positions for laboratory assistants were reasons given for teachers’ intense workloads. This study implies a need to provide government and non-government schools with necessary equipment for doing practical work; to appoint sufficient teachers with higher studies and training that includes practical work in physics; to create positions for laboratory assistants; to set up classrooms with a smaller number of students; and to develop awareness of the value of practical work among school administration and among physics teachers.