Nowadays, a wide variety of chemicals has emerged because of increasing industrial and human activities. Thus, environmental chemistry laboratories performing analytical measurements need rapid and sensitive methods more than ever to get reliable quantitative data. For this purpose, a purge and trap gas chromatography–mass spectrometry (GC‐MS) method was developed and validated for the rapid, simple, and sensitive determination of the presence of naphthalene and its derivatives in waters. The method validation was based on specificity, calibration curve linearity, limit of detection (LOD) and limit of quantification (LOQ), accuracy (recovery), precision, matrix effects (MEs), and measurement uncertainty. This method showed excellent linearity from 1.00 to 40.00 μg/L except naphthalene (0.50–40.00 μg/L) because the correlation coefficients were higher than 0.997 for all analytes. The LOQ values varied from 0.312 to 0.746 μg/L, and the LOD values changed from 0.094 to 0.224 μg/L with relative standard deviations (RSDs) for all compounds below 10% (3.12–7.46), respectively. Recoveries ranged from 81.9% to 95.6%, and repeatability and reproducibility (in terms of RSD for six measurements) were lower than 10% in all cases. F test was subjected on the related data at 95% confidence level, and no statistically significant difference was observed. There was no critical ME (recovery varied from 80% to 110% in all matrices). In measurement uncertainty, the expanded uncertainties of each analyte were changed in the range of 0.39–0.52 μg/L, and the calibration curve and repeatability had dominant effects on the combined uncertainty. The application to real samples was successfully assessed by the developed method. These results indicate that the developed method is suitable for the determination of naphthalene and its derivatives in waters.