Thin-film transistors (TFTs) based on solution-processed metal oxides have been widely studied in recent years. The growing interest on these devices is related to their potential use in digital electronics, optoelectronics, sensors and biosensors. These materials have several advantages, such as low-cost, low manufacturing temperature, high optical transmitance in the visible spectrum [1,2] and, in some situations, compatibility to flexible substrates. We report herein the manufacture of TFTs by depositing thin layers onto indium tin oxide (ITO)/glass substrates: insulating/dielectric layer (Al2O3), semiconductor (ZnO) and metallic electrodes (Al). The active layer semiconducting material (ZnO) was deposited by spray-pyrolysis technique, using an organic precursor solution of zinc acetate dihydrate in methanol [1]. The insulating/dielectric layer was formed by spin-coating deposition of an organic precursor which results on aluminum oxide (Al2O3) ultrathin films (below 10 nm). The ITO gate electrode was deposited by magnetron RF sputtering whereas the Al drain and source electrodes were deposited by thermal deposition in high-vacuum conditions. Transistor characterization resulted in saturation mobility (μsat) values higher than 100 cm2V-1s-1, threshold voltage (VTH) of 0.1 V, on/off ratio superior to 105 and optical transmittance of the TFT channel higher than 80% in the visible region. The obtained results contribute to the development of transparent TFTs with low operating voltage (below 3 V), enabling potential applications in logic circuits and digital electronics. Acknowledgements: This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001Fundação de Amparo à Pesquisa no Estado de São Paulo - FAPESP2019/08019-9