A highly sensitive, accurate and simple spectrophotometric method was established for determination of naproxen (NAP). The method involved ion-pair complex formation between naproxen and bromophenol blue (BPB). The colored product was measured at 432 nm. The reaction conditions were optimized. The absorbance was found to increase linearly with increase in concentration of NAP which was corroborated by correlation coefficient value. Beer’s law was obeyed in the concentration range of 1-110 µg mL-1 with molar absorptivity of 9.756×103 L mol-1 cm-1. The limits of detection (LOD) and quantitation (LOQ) for the proposed method are 0.292 and 0.973 µg mL-1, respectively. Recovery of the method was carried out by standard addition method. Recovery studies and statistical data proved the accuracy, reproducibility and the precision of the proposed method. The common excipients did not interfere in this analysis. Hence the method is useful for routine estimation of naproxen in pharmaceutical formulation and human serum samples.