This paper discusses supervision of services as the rot of public secondary school libraries in Nigeria. The concept of supervision of services, its upshot in public secondary schools system and the various supervision strategies that when applied could place the libraries in public secondary schools on a better pedestal were examined. The paper concludes that as the 21" century public secondary schools are expected to be productive in a dynamic and changing global village, the libraries must have their services well supervised for the attainment of functionality and utility.