Maize (Zea mays L.) is one of the most widely cultivated cereal crops, serving as a staple food, animal feed, and industrial raw material across the globe. Its physiological processes play a crucial role in determining growth, development, and yield potential under diverse environmental conditions. This chapter explores key aspects of maize physiology, including photosynthesis, water and nutrient uptake, growth dynamics, and stress responses. Special emphasis is placed on how maize adapts to abiotic and biotic stresses, such as drought, heat, and nutrient deficiencies, and the physiological mechanisms that enable resilience. Additionally, recent advancements in crop improvement strategies, including genetic and agronomic interventions to enhance maize productivity, are discussed. A comprehensive understanding of maize physiology is essential for optimizing management practices, improving resource-use efficiency, and ensuring global food security.