The fuel supply chain is a vital infrastructure demanding real-time traceability to ensure integrity, transparency, and security of the delivery. Traditional fuel supply chains are often plagued by complexities and vulnerabilities, including fraud, theft, and operational inefficiencies that require innovative solutions. This paper proposes Truckchain, a blockchain-powered Internet of Things (IoT) system designed to overcome these challenges and improve fuel supply chain traceability, transparency, security, and efficiency. Using Swala Logistics as a case study, Truckchain integrates IoT sensors with blockchain technology to create an immutable, decentralized, and transparent real-time tracking system that monitors fuel from loading to delivery. The system captures critical data, such as temperature, fuel levels, and delivery quantities, and securely stores them on a blockchain to ensure the integrity and immutability of the data. Truckchain enhances stakeholder trust through complete transparency, improves regulatory compliance, and facilitates effective anomaly detection and loss prevention by providing comprehensive real-time monitoring functionality. This paper details the architecture, design, implementation, and evaluation of Truckchain, highlighting its potential to enhance fuel supply chain efficiency and security significantly.