This chapter provides a comprehensive overview of the humanitarian supply chain, defining its scope, characteristics, and key stakeholders. It establishes the humanitarian supply chain as a critical system for assessing needs and managing the flow of information, goods, and resources to alleviate suffering in disasters and crises. The chapter delineates the fundamental differences between humanitarian and commercial supply chains, arguing that while they share operational strategies (e.g., logistics, inventory management), their core motivations—profit maximization versus fulfilling human need—are distinct. A historical perspective is offered, alongside a detailed examination of the central role played by major international organizations. It concludes by analyzing the critical similarities and differences with commercial supply chains, highlighting unique humanitarian challenges such as extreme urgency, profound uncertainty, and complex external factors like geopolitics. This foundation is essential for understanding the evolving challenges facing twenty-first-century humanitarian operations.