In this paper, we have developed a stacked Pr2O3/SiOxNy gate dielectric into low-temperature poly-Si thin-film transistors (TFTs). High-performance TFT devices can be achieved including a high effective carrier mobility, high driving current, small subthreshold swing, and high ION/IOFF current ratio. This phenomenon is attributed to the smooth Pr2O3/poly-Si interface and the low interface trap density provided by N2O plasma treatment. The presence of an SiOxNy buffer layer also enhanced the electrical reliability of the Pr2O3/poly-Si TFT. All of these results suggest that a high-k Pr2O3 gate dielectric prepared the buffer layer is a good candidate for high-performance TFTs.