Nanoencapsulation is an advanced technique that involves enclosing bioactive compounds within nanoscale carriers to enhance their stability, bioavailability, and controlled release. It plays a crucial role in protecting sensitive compounds from environmental factors such as oxidation, temperature fluctuations, and moisture while improving their solubility, targeted delivery, and functional properties. The choice of encapsulating materials, including natural and synthetic polymers, lipids, and inorganic matrices, significantly influences the physicochemical characteristics and effectiveness of nanoencapsulated systems. This chapter provides a comprehensive overview of various nanoencapsulation techniques categorized into polymer-based, lipid-based, inorganic-based, and hybrid approaches. The fundamental principles, fabrication methods, and advantages of these techniques are discussed, highlighting their applications in pharmaceuticals, food, cosmetics, and agriculture. Recent advancements, such as the development of multifunctional nanocarriers and stimuli-responsive encapsulation systems, are also explored. Additionally, challenges such as scalability, regulatory concerns, and safety considerations are addressed to provide a holistic perspective on the potential and limitations of nanoencapsulation technology.