The targeted delivery of sensitive bioactive compounds, including pharmaceuticals, nutraceuticals, and therapeutic agents, is frequently obstructed by various factors, such as exposure to detrimental processing conditions, environmental stresses (including heat, light, oxygen, and moisture), and inappropriate storage conditions. The stability, bioavailability, and therapeutic effectiveness of the active ingredients are seriously jeopardized by these variables. Protein-based nanoparticles have become a viable way to address these issues in recent years. Protein nanoparticles have a number of benefits as they are non-toxic, biocompatible, and biodegradable. These benefits include low production costs, simple functionalization, small particle size for improved cellular uptake, and quick removal from the body without triggering an immune reaction. Additionally, proteins offer functional groups that enable the regulated release and targeted distribution of encapsulated bioactives. Protein nanoparticles can be synthesized using a variety of techniques, which include emulsion methods, nano-spray drying, protein encapsulation, template-induced synthesis, nanoprecipitation, crosslinking, adsorption, and desolvation. Regarding structural stability, release kinetics, and encapsulation efficiency, each method has special advantages. Depending on the use and the physicochemical makeup of the medication, a variety of proteins can be used. Both hydrophilic and hydrophobic substances can be encapsulated by these protein nanoparticles, increasing their solubility and preventing premature breakdown. The manufacture, characterisation, and present uses of protein-based nanoparticles in the targeted delivery of bioactive substances are examined in this chapter.