Products and kinetics of naphthalene and 2-methyl naphthalene ozonation in acetic acid were studied. It was shown that these compounds react with ozone mainly at the aromatic ring yielding peroxide products. In the oxidation of naphthalene, traces of 1,4-naphthoquinone and phthalic acid were found in addition to peroxides. In the case of 2-methylnaphthalene, the products of methyl group oxidation, 2-naptithoic acid and 2-naplithaldehyde, were also identified. According to the suggested oxidation scheme, ozone is consumed not only in the reaction with the substrate but also with its oxidative degradation products.