All aspects of work, and even play, require an allusive entity called supervision. Supervision models vary from loosely organized structures to strict activity overview. The `instructional supervisory role' may be performed by one or several individuals from within or without the school, all working to assist school personnel improve their performance (for example, employees from the National Inspection System). As in other countries, Turkey has private and state schools. Both are subject to regular inspection by a centralized National Inspection System. However, in order to overcome shortfalls of the National Inspection System, private schools have had to establish internal teacher evaluation programs. The purpose of this paper is to assess current school-based supervision practices in one private school. It is intended to provide a school-based supervision model through which private secondary schools may improve their performance, accountability, and enhance teacher quality.