<p>This study aimed to develop and validate a UV-Vis spectrophotometric method for quantifying resveratrol in whey protein microparticles. The method was validated in accordance with the International Conference on Harmonization (ICH) guidelines for specificity, linearity, limits of detection and quantification, accuracy, intermediate precision, and reproducibility. The method showed linearity over the concentration range of 0.6-8.0 mg L^-1. The adjusted determination coefficient (R²_adj) was 0.9801 ± 0.005. This value was calculated as the mean ± standard deviation from a calibration curve of six resveratrol concentrations, each measured in triplicate. Limits of detection and quantification were 0.1 mg L^-1 and 0.3 mg L^-1, respectively, and the average recovery was greater than 87%. The validated method was applied to determine the encapsulation efficiency and loading of resveratrol in spray-dried whey protein microparticles, yielding 89 ± 4% encapsulation efficiency, corroborated by physicochemical and morphological characterization. As a proof-of-concept, the microparticles were incorporated into orodispersible tablets, which showed only minor changes in color, mechanical properties, and disintegration behavior in simulated salivary fluid. These results demonstrate that the proposed UV-Vis method is a simple, reliable, and suitable alternative for resveratrol quantification in food-grade encapsulation systems.</p>