The research examined the effect of supply chain management on firm’s operational performance in Nigeria manufacturing companies with specific interest on supply chain strategy and supply chain flexibility. A random effect model was developed to examine whether there is a significant effect on the variables identified, and the level of significance that exist in the variables. This study adopts an ex post-facto type of descriptive research design using Secondary sources to generate the data. The data were gathered from the annual report of manufacturing companies between 2011 and 2016. Findings revealed that supply chain management does not have a significant overall effect on operational performance at Prob value =0.343 which is above the sig. level of <.005, and the magnitude of variation which supply chain management cause on operational performance is 7.6% for all the companies samples which is significantly low. Hence, it is recommended that the management of a company’s supply chain do not necessarily affect their operations; thus organizations can adopt a combination of strategies and flexibilities in their level of operation.