Proso millet (Panicum miliaceum) is a highly nutritious and versatile grain that has attracted considerable interest due to its health benefits and wide range of applications. This chapter provides a comprehensive overview of Proso millet, focusing on its chemical composition, starch isolation techniques, modification methods, functional properties, and diverse applications. Proso millet is characterized by a rich profile of proteins, vitamins, minerals, and majorly starch. The isolation of starch from Proso millet is typically performed using alkaline and acid steeping methods, which significantly affect the yield and quality of the extracted starch. Chemical modifications, such as esterification and acetylation, enhance the functional properties of Proso millet starch, while physical modifications, including heat moisture treatment and high-pressure processing, further refine its other properties. The starch derived from Proso millet is notable for its high-resistant and slowly digestible starch, which enhance its functionality in various food products, including pasta, bread, and porridge. Additionally, Proso millet starch is utilized in nonfood applications such as animal feed, biodegradable materials, and biofuels. The ongoing development of starch modification techniques aims to broaden the potential uses of Proso millet, underscoring its value as a versatile ingredient in both food and nonfood industries.