Education is an essential process for human resource development. In this rapidly changing world things and processes are under swift transformation. Teacher, teaching and the classroom can't remain unaffected from these worldly changes. Teaching is a systematic and well thought purposeful process to make the environment favorable for learning. Quality of learning is always linked with the quality of teaching in general terms. This causal-comparative study was designed to explore the effect of teachers' professionalism on their quality of teaching and engagement in the classrooms. Two self-developed questionnaires were used for data collection from sampled primary school teachers (N=1230). The analysis of data revealed that teachers’ professionalism has a positive effect on teachers' classroom engagement as well as quality of teaching. On the basis of results of this study it is proposed that during the process of teachers' recruitment the attitude of teachers towards teaching and level of their professionalism may be taken care of before offering them entry in the school system. The pre- service and in-service training may be based on such activities that can boost the nature and level of professionalism among primary school teachers.