<p>In today’s competitive environment, emerging technologies such as the Internet of Things and blockchain can enhance transparency, traceability, and information management in supply chains. Based on this perspective, a multi-period and multi-product virtual closed-loop supply chain optimization model is developed. In this model, IoT and blockchain are incorporated as traceability and information-management infrastructures that facilitate product tracking and information transparency across the supply chain. The model is formulated as a mixed-integer linear programming model with a four-echelon forward structure and three-echelon reverse structure. Demand uncertainty is managed using a fuzzy approach. The problem is solved for small- and medium-scale instances using GAMS. For large-scale instances, due to NP-hard nature of the problem, the Grey Wolf Optimizer algorithm is used. To examine the role of Internet of Things and blockchain technologies in the supply chain, two comparative studies are conducted: the first study analyzes the simultaneous implementation of these two technologies. The second study focuses on the role of blockchain. The results of the comparative studies indicate that integrating the Internet of Things and blockchain enhances supply chain sustainability, transparency, and profitability.</p>