This study was aimed at investigating the influence of instruction supervision practice on teachers’ classroom performance in Shinyanga Urban District in Tanzania. The study objectives were; to identify instructional supervision methods employed to improve teachers’ classroom performance; to examine teacher’s perceptions towards instructional supervision practices; to determine the influence of instruction supervision on teachers’ classroom performance; and to asses’ different ways to improve instruction supervision practices in schools. Mixed research approaches with descriptive survey design were utilized in the study. Questionnaires and interview were the main instruments employed in the study. Piloting was carried out using test retest technique to determine the validity and reliability of instruments. The researcher obtained a sample of 5 public secondary schools, 5 heads of public secondary schools, 5 wards education coordinators, 1 district education officers, two education quality assurers and 30 teachers through both simple random and purposive sampling techniques. The study findings revealed that instructional supervision practices have direct influence on enhancing teachers’ classroom capability. Hence the majority of participants (83%) agreed that the practice helps teachers to teach more effectively, improve their pedagogical skills and evaluate their teaching progress. The study recommended that the government should provide regular supervisory training in schools and education colleges to enable teachers to be aware of the practice. The study concludes that instructional supervision should be taken as a priority in schools in order to improve the quality of teachers.