This dataset contains raw and processed chromatographic data generated during the development and validation of a reversed-phase liquid chromatographic method for the determination of major whey proteins (α-lactalbumin, β-lactoglobulin, and bovine serum albumin) in dietary supplements. The dataset includes chromatographic runs, calibration data, repeatability studies, detection limit evaluation, and sample analyses. All data are organized in Microsoft Excel spreadsheets and correspond directly to the experiments described in the associated publication.