The paper has investigated how operations of the Small and Medium Enterprises (SMEs) in Nigeria are influenced by supply chain management (SCM) practices. SCM plays a vital role in efficiency, competitiveness and service delivery in SMEs, however, there has been a paucity of empirical literature regarding the integrated effect of SCM in the Nigerian context. According to the existing literature, supplier relationship management, inventory management, information sharing, and logistics coordination play a crucial role in improving the performance of operations. Quantitative survey design was used and 200 structured questionnaires have been given to SME managers, 191 of them were duly filled and this gave a response rate of 95.5. Descriptive statistics, Pearson correlation, and multiple regression were used to analyze data in order to investigate the relationship between SCM practices and operational performance. The findings showed that operational performance was positively and significantly affected by all the dimensions of SCM. The impact of Supplier Relationship Management (SRM) was strong (β = 0.42, r = 0.671, p < 0.001), then, Information Sharing (IS) (β = 0.35, r = 0.619, p < 0.001), Inventory Management (IM) (β = 0.31, r = 0.543, p < 0.001) and Logistics and Distribution Management (LDM) (β = 0.29, r = 0.502, p < 0.001). The integrated SCM model accounted 61% of the operational performance (R2 = 0.61, F (4,186) = 72.34, p < 0.001). To sum up, efficient and combined SCM practices play a great role in improving the efficiency of SME operations in Nigeria. SMEs are advised to enhance supplier cooperation, inventory management, information exchange, and better logistics system. Also, the staff training on the best practices in SCM must be done continuously to maintain performance and quality of services. Keywords: Supply Chain Management, Operational Performance, SMEs, Supplier Relationship, Inventory Management, Information Sharing, Logistics, Nigeria