Educational supervision is very vital in curriculum delivery to ensure quality output in terms of students’ academic performance and teachers’ development. Education supervision has been bedeviled with series of problems since the takeover of schools by Nigerian government in 1976. The problem of poor teachers’ development in Nigerian public secondary schools has been the concern of the government and the society at large in which different scholars had suggested allocation of more fund to the educational sector, employment of more teachers and provision of instructional materials to the school, yet with no positive result. Therefore this study investigated the use of supervision as a tool in ensuring teacher’s development in Ondo State public secondary schools. Qualitative research approach of the survey type was used. While purposive sampling method was used to sample four secondary schools in Ondo State. The findings revealed that schools with adequate supervision are of better quality in terms of students’ academic performance, staff development and students’ discipline. The study therefore recommended that school supervision should be a daily activity in the school. Also, educational supervisors should not be interested in finding faults of teachers but more importantly, dialogue with teachers to identify their strengths and weaknesses in order to improve on their professional knowledge, skills and experiences.