Abstract The highly attractive properties of polymer–clay nanocomposite (PCNs), such as high dimensional stability, heat deflection temperature, gas barrier performance, reduced gas permeability, optical clarity, flame retardancy, recommend for several different applications such as food packing, biomedical applications, wastewater pretreatment, electricals/electronics, optoelectronics, sensors, and automobiles. This chapter presents a review of the recent advances in PCNs research study including their different industrial and technological applications. We will not attempt to cover in detail all of these PCNs and their applications but will explain the main applications of them as a whole with their numerous practical examples. The different techniques used to prepare PCNs and their characterizations are also reviewed.