Supervision is an effort to help the development and upgrading of the parties in supervision so that they can carry out tasks predefined activities efficiently and effectively. The purpose of supervision is toprovide assistance to subordinates directly, so that subordinates have enough stock tobe able to carry out tasks or jobs with good results and orient, train workers, lead,provide direction, and develop the skills of personnel. The supervisory role is one of the functions of a school operation that has been and continues to be a very challenging aspect of administration in secondary schools. This challenge involves a continuous process of assisting teachers to improve their instructional performance in accordance to the professional code established by the Ministry of Education. Supervision is very important in schools to ensure that the standards set by the Ministry are adhered to and not only the institutional goals but also the national goals are met. Therefore, the researcher uses qualitative supervision as its method to examine its practices of utilizing thet heory of developmental supervision. This study aims to: (1) know the learners planning, (2) describe the process of admission of new students, (3) determine the grouping of students, (4) determine the mutation settings and learners drop out, (5) determine disciplinary settings and student discipline, (6) knows coaching learners, and (7) describe the process of assessing students in the One Roof School.