During the past few decades, the interest in flexible and transparent electronics has arisen, and ZnO-based devices present a great potential among these technologies. In this study, ZnO nanoparticles were used to integrate thin-film transistors, whereas cross-linked poly(4-vinylphenol) (PVP) and PECVD-SiO2 were used as a gate dielectric layer. Unfortunately, there are reliability concerns in ZnO devices, such as aging and hysteresis. In this study, an experimental investigation of the hysteresis in the transfer characteristic is performed. It was observed that the hysteresis direction is affected by temperature variation when the polymeric dielectric is used. The PVP bulk polarization, the traps in nanoparticles and at the polymeric dielectric interface, as well as the desorption of oxygen molecules in the surface of the nanoparticles, were attributed as the main cause of the hysteretic behavior.