This study examined the adequacy with which instruction is being supervised, the quality of interpersonal relationships between supervisors and teachers and teachers' suggestions for improving the instructional supervision in Nigeria. The sample consisted of 361 teachers from the Delta Central Senatorial District, of Delta State, Nigeria. Frequency, percentage, mean and standard deviation were used to compute and analyzed data collected. Findings from the study revealed that instructional supervisors are not performing their functions such as regular classroom visitation, monitoring of teaching method and teachers' logbooks, in public secondary schools in Delta Central Senatorial District and that adequate interpersonal relationships do not exist between secondary school teachers and instructional supervisors. The findings reflect the related and similar theme in research on conditions of service of teachers, particularly the lack of adequate support from those charged with instructional supervisory responsibilities. Based on the findings, recommendations were made that more resources should be devoted to instructional supervisors to strengthen their supervision capacity.