Supervision is a positive process in which the major focus is upon quality student learning resulting from a long-term investment in the growth and development of the professional teaching staff. Supervision of instruction is multifaceted interpersonal process dealing with teacher‟s behavior, curriculum, grouping of students and teachers utilization of all skills for set targets. In Pakistan the instructional supervision is the duty of school principals, headmasters and the education officers in addition to their administrative role of maintaining school discipline and provision of physical facilities. This study was conducted to assess the role of instructional supervisors in promoting the effective teaching practices in girl‟s high schools of Khyber Pakhtunkhwa. The major objectives were: (1) to investigate the present teaching practices in government schools; (2) to explore the qualities, efforts and efficiencies of instructional supervisors; (3) to determine the allocated time and supervisors priorities about instructions; and (4) to investigate teachers views about supervisors strategies, level of interest for the improvement of teaching learning process The Population of the study consisted of 25 District Education Officers of Khyber Pakhtunkhwa, 274 principals of Girls high schools, 2084 Senior English Teachers of these high Schools and all the 71999 female students of class 9th and 10th enrolled in these274 schools for female in the province. The sample was randomly selected. Seven District Education officers, 95 high school principals,468 teachers working against SET (general) posts in selected schools from each category in Khyber Pakhtunkhwa, and 2440 students being taught by teachers, were selected as sample for the study. Data were collected by the researcher through personal visits to the sample schools. District Education officers were interviewed and three close-ended questionnaires for principals, teachers and students were distributed and recollected afterwards. The collected data were organized, tabulated. The Percentage and Chi-Square test was applied to get reliable results through the SPSS program. Major findings of the study indicated that all the education officers were well aware about their role and responsibilities as instructional supervisors and they had proper knowledge and skills to perform their role as Instructional leaders but due to their hectic schedules, they could not manage to supervise the schools properly. There was no proper way to communicate the knowledge of instructional objectives to the school principals and to the subject teachers due to lack of ways and time for interaction. The present teaching practices in schools were mostly traditional and due to lack of resources and interest, teachers were reluctant to use new teaching methods and adopt new techniques. Most of the teachers and the instructional supervisors were aware of the standards of teaching for effectiveness to some context. They were not implementing these standards properly and the supervisors were not using evaluation techniques properly. Students and teachers were found highly motivated for teaching and learning system of giving reward was not effectively implemented and parental involvement in the teaching learning process was not found. Students‟ performance and achievements were the criteria used mostly to judge the effectiveness of the teaching and the same criteria was adopted by the education officers to measure the performance of school principals as instruction supervisors.