The dielectric properties of ZrO2–Al2O3 nanolaminates, deposited via atomic layer deposition, and their impact on the performance and stability of indium gallium zinc oxide and zinc tin oxide amorphous oxide semiconductor thin-film transistors (TFTs) are investigated. It is found that nanolaminate dielectrics can combine the advantages of constituent dielectrics and produce TFTs with improved performance and stability compared to single layer gate dielectrics. It is also found that TFT performance and stability are influenced not only by the chemical composition of the gate dielectric/channel interface but also by the thickness and composition of the laminate layers in the dielectric near the interface.