The study attempted to find out the impact of capacity building of teachers of Government Primary schools on classroom teaching. The objectives of the study were to find out the strengths and weaknesses of the capacity building initiatives for professional development of teachers of Govt: Boys` Primary Schools in district Swat and to make recommendations for improving the current efforts for capacity building of primary school teachers. Capacity is developed when individuals are motivated to use knowledge, skills and resources in order to enhanced organizational objectives, The population of the study included 841 Headmasters of Government Boys` Primary Schools, 3034 senior teachers and 50535 students. Of those 252 (30%) Headmasters, 910 (30%) Senior Teachers and 15160 (30%) students were randomly selected for sampling reason being that total population of teachers could not be covered. An opinionnaire containing eleven statements was handed over to Head Masters, a questionnaire containing eleven questions were handed over to the teachers who had received training and a checklist for classroom observation of 5th class students of 101 primary schools in district Swat. The relevant literature was reviewed, which provided indicators for development of tools. The data obtained were quantified and described. In order to measure the internal reliability of the opionionnaire, Cronbach’s Alpha Reliability Test was applied for estimating the reliability of the data. The value of Cronbach Alpha was 0.89, which indicated a high level of internal reliability. The Chi-Square Test of Association was also applied for checking the results to show association between the responses of Head Masters and Teachers. It showed that there were no significant differences in the responses of both Head Masters and Teachers. The results revealed that Head Masters could play more effective role for school effectiveness by developing clear vision; providing instructional feedback to teachers; effective monitoring and supervisory mechanism; setting a democratic environment conducive to teaching learning process and involving the stakeholders in decision-making. The results of the study further indicated that school effectiveness owed itself to capable Head Masters, committed staff, non-political intervention, a procedure of incentives and disincentives, positive feedback to teachers and last, but not the least, a continuous instructional supervision to what happened in classroom. The recommendations for improving classroom teaching required continuous on-the-job training, commitment of teachers to the teaching profession and improved pedagogical skills of teachers as well as updating classroom management.