The study assessed the interpersonal skills of the school principals in terms of role management, learning and training, understanding and motivating teachers, positive teachers' attitudes, and problem-solving techniques, and their effects on teachers' performance. Responses were gathered from 706 teachers and eight principals, a total of seven hundred fourteen (714) respondents from two schools per school category. The descriptive research design and statistics were utilized to gather, present, and interpret the necessary data. Data revealed that the school principals and teachers have positive interactions and relationships and that the performance of teachers is affected to a very high extent. Because of this, teachers rarely encountered interpersonal-related challenges with their school principals, and that the school principals, as heads of the schools, have never experienced any of these challenges. As there is no perfect persona in the world so as to school heads and teachers, the researcher recommended both parties adhere to professional acts and codes of ethics for professional teachers.