Abstract: Secondary school heads are assumed to play an important role in influencing student performance within their academic institutions. In Kenya, the school principal is considered to be in charge of guiding both teachers and students toward a common goal. In most cases, principals devise a variety of strategies to assist them in leading their institutions to success, one of which is instructional supervision. However, it has not been determined whether or not instructional supervision influences the performance of girls in Bungoma County secondary schools, which serves as the foundation of this research.