The study investigated the "Influence of Instructional Supervisory Role Performance of Principals on teachers performance in Private Secondary Schools in Kaduna State, Nigeria" the objectives of the study were to examine the influence of supervisory role performance of principals on teachers' lesson plan, find out the influence of supervisory role performance of principals on classroom visitation and determine the influence of supervisory role performance of principals on teachers use of instructional materials in private Secondary Schools in Kaduna State, Four (4) research questions and four (4) hypotheses were raised for the study, Descriptive survey research design was used in the study. The population for the study was One Thousand Two Hundred and Fifty-Four (1254) respondents, comprised of 72 principals, 1,168 teachers and 14 ministries of education officials. A sample of 386 respondents (22 principals, 350 teachers, and14 Ministry of Education officials) was selected using simple random sampling techniques. A structured questionnaire with a five-point Likert scale was used for data collection. Supervisors and professionals in the department validated the questionnaire. Pilot study was carried out in Giwa education zone. The data for pilot study was analyzed. The bio data of the respondents were analyzed using simple percentage and frequency while descriptive statistics (mean score and standard deviation) was used to answer the research questions. One Way Analysis of Variance (ANOVA) was used to test all null hypotheses at 0.05 alpha level of significance. Out of four hypotheses tested, two were retained while two were rejected. Findings revealed that instructional supervisory roles of principal's on teacher" lesson plan influenced their performance, principal's classroom visitation influenced teachers" performance and Principal's supervisory roles on the use of instructional materials influenced teacher's performance. The research concluded that instructional supervisory roles of principal's influence teacher's performance in private secondary schools in Kaduna State. Based on the findings, it was recommended among others that. Educational administrators and school owners should organize seminars, workshops and in service to educate principals of both private and public secondary schools on the current and new format of writing lesson plan and improve their instructional supervision in the school system. Instructional materials like textbooks needed for effective teaching and learning should be made available to schools, adequately supervised by the principals, and effectively utilized by the teachers.