Silk protein nanoparticles (SPNs) have emerged as promising carriers in cosmetics and personal care due to their biocompatibility, biodegradability, and ability to enhance the stability and efficacy of active ingredients. This chapter provides an overview of SPNs, focusing on the structure and properties of silk fibroin and sericin, as well as the methods used for nanoparticle synthesis, including their advantages and disadvantages. A significant part of the chapter discusses the application of SPNs in cosmetics, highlighting their role in delivering active compounds such as resveratrol, vitamin A, niacinamide, and plant extracts. These nanoparticles improve the stability, bioavailability, and penetration of bioactive substances, enhancing their antioxidant, moisturizing, and antimicrobial effects. Overall, the discussed research demonstrates that SPNs offer innovative solutions for cosmetics and personal care, providing enhanced functionality and stability of active ingredients. Their proven benefits make them a valuable tool for next-generation cosmetic formulations.