This chapter focuses on the development of nanomaterial-enhanced phase change materials for latent thermal energy storage systems. Here, it is started with the working principle of phase change materials, types (organic and inorganic materials), and the importance of improving the thermal conductivity of the phase change materials. Various heat transfer techniques employed for accelerating the melting and solidification of the phase change materials are briefly discussed. Among different enhancement techniques, nanomaterials used for improving the thermal conductivity of the phase change materials are highlighted herein. The effects of concentration, size, morphology, and types of the nanomaterials toward the thermal conductivity enhancement of the phase change materials are reported comprehensively. At the end of the chapter, the applications of nanomaterial-embedded phase change materials are discussed in detail.