Contamination with naphthalene, as one of polycyclic aromatic hydrocarbons (PAHs), was considered as an important health issue due to its mutagenic and carcinogenic potential . In this essay, we focused on the photo catalytic degradation of naphthalene in various mediaand in presence of various photocatalysts. Zinc oxide nanoparticles (ZnO NPs) was prepared and utilized as efficient photocatalyst to convert naphthalene into safer compounds. Transmission electron microscopy (TEM), UV-VIS spectroscopy and x-ray diffraction (XRD) were used to evaluate the photocatalyst in its as-prepared state. The length of the photocatalytic degradation process, the amount of loading catalyst and the intensity of the light are all influencing variables, were investigated. The optimum photocatalytic degradation of 21.53 mg/L naphthalene in different media was carried out at pH 12 with maximum loading catalyst dose of 666.666 mg/L. In case of naphthalene aqueous ethanolic solution, a faster photochemical kinetic was observed in presence of ZnO NPs and more than 90% of photocatalytic degradation percentage was reached in 395 min. Gas chromatography-mass spectrometry was used to identify the byproducts of butyl phthalate (95.38%). (GC–MS). The results of the kinetic studies showed that the pseudo-first order rate expression and Langmuir-Hinshelwood model were both used to describe the photocatalytic degradation process.