This chapter critically analyzes the complex nexus between food waste and food insecurity within the contemporary global food system. Examining the intricate relationship between these two critical issues, this chapter investigates the main causes and consequences of food waste for food insecurity on a global scale. It explores how food waste contributes to food shortages, price volatility, and limited access to nutritious food, particularly for vulnerable populations. The chapter further analyzes existing policies and initiatives aimed at reducing food waste and improving food security, evaluating their effectiveness and identifying potential gaps. Finally, it explores the implications of incorporating robust anti-food waste measures in building a sustainable food system and achieving sustainable development goals (SDGs), particularly SDG 12: Responsible Consumption and Production and SDG 2: Zero Hunger. By understanding this critical interlinkage, this chapter aims to inform the development of more effective and integrated strategies to address both food waste and food insecurity, contributing to a more just and equitable global food system.