This paper reports the development of nanoporous tungsten trioxide (WO₃) Schottky diode-based gas sensors. Nanoporous WO₃ films were prepared by anodic oxidation of tungsten foil in ethylene glycol mixed with ammonium fluoride and a small amount of water. Anodization resulted in highly ordered WO₃ films with a large surface-to-volume ratio. Utilizing these nanoporous structures, Schottky diode-based gas sensors were developed by depositing a platinum (Pt) catalytic contact and tested towards hydrogen gas and ethanol vapour. Analysis of the current–voltage characteristics and dynamic responses of the sensors indicated that these devices exhibited a larger voltage shift in the presence of hydrogen gas compared to ethanol vapour at an optimum operating temperature of 200 °C. The gas sensing mechanism was discussed, associating the response to the intercalating H⁺ species that are generated as a result of hydrogen and ethanol molecule breakdowns onto the Pt/WO₃ contact and their spill over into nanoporous WO₃.