The physiology of fruits and vegetables plays a crucial role in their ripening process. Ripening, a complex biochemical phenomenon, is characterized by a series of physiological changes, including enzymatic activity, respiration rates, cell wall modification, and the synthesis of flavor compounds. Ethylene, a plant hormone, is a key regulator in the ripening process, triggering the expression of genes responsible for the conversion of starches to sugars, the degradation of chlorophyll, and the formation of color pigments such as carotenoids and anthocyanins. Furthermore, environmental factors such as temperature, humidity, and light significantly impact the rate and uniformity of ripening. This chapter explores the biochemical and physiological mechanisms underpinning the ripening of fruits and vegetables. Understanding the intricacies of ripening is critical for improving storage techniques, reducing post-harvest losses, and enhancing the nutritional and sensory qualities of fruits and vegetables. Additionally, it provides insight into the potential for genetic engineering and biotechnology, where advances could allow for the development of varieties with optimized ripening characteristics, improved nutritional content, and enhanced resistance to diseases and pests for better shelf life and marketability.