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Tungsten oxide (WO3) thin films find applications in a variety of fields, including chromism, gas sensing, and photoelectrochemistry. In the context of each application, the necessity arises for the identification of specific material properties. In this study, we propose a sol–gel methodology that facilitates the modulation of material properties through the precise manipulation of synthesis parameters. The calcination temperature, template concentration, and number of dip coating steps were found to have a significant impact on the crystallinity, (002) facet exposure, surface area, band gap, and absorption efficiency of the mesoporous WO3 thin films. In the context of photoelectrochemical water oxidation, it has been determined that the crystallinity, band gap, and light absorption of the material are positively correlated with enhanced bulk processes. Photocurrent values of up to 3.75 mA cm–2 at 1.23 V vs RHE under AM 1.5 G illumination were achieved, while external quantum yields of 58% were also obtained. The systematic correlation between synthesis parameters and material properties, as outlined in this study, offers a straightforward and efficient method for adjusting WO3 thin film properties to meet specific application requirements.