This chapter presents an overview of electroless (EL) Ni-P nanocomposite coatings, focusing on their preparation, challenges, and issues on particle incorporation in the metal matrix in terms of dispersibility of nanoparticles in the plating bath, interaction between the nanoparticles and the EL Ni-P matrix during deposition, influence of incorporation of nanoparticles on the characteristics of EL Ni-P nanocomposite coatings, and applications of EL Ni-P nanocomposite coatings. © Springer International Publishing Switzerland 2016.