Nanoparticles, with their dimensions generally ranging from 1 to 100 nm, exhibit superior physical and chemical properties compared to their bulk structures due to their high surface area and quantum effects. These characteristics enable their widespread use in various fields such as environmental science, agriculture, biomedicine, textiles, and pharmaceuticals. Especially in the field of textiles, nanoparticles make significant contributions to the advancement of functional textiles by imparting enhanced properties to fabrics, such as stain resistance, flame retardancy, ultraviolet (UV) protection, and antibacterial activity. This book chapter addresses the definition and classification of nanoparticles, as well as their synthesis using physical, chemical, and biological methods. Furthermore, it provides an overview of the integration of nanoparticles into textiles and their applications in various fields, including water purification, sensors, UV protection, and energy storage.