For consumer safety reasons, cosmetics that are exposed to light are evaluated with respect to phototoxicity and/or photoallergy (photosensitization). For perfumes/aftershaves, however, these tests are not performed with the cosmetic product but only with single fragrance compounds, which may influence the outcome. In the presence of a sensitizer, photoinduced oxidation of unsaturated fragrances might result in the formation of unwanted products. Therefore, using real samples, we studied the photodegradation of the common fragrance octahydro tetramethyl naphthalenylethanone (OTNE) under in vitro irradiation, during indoor storage, and after application on skin. OTNE and its photoproducts were determined by liquid chromatography (LC) coupled to diode array detection (DAD). Whereas OTNE itself was photostable, irradiation in the presence of a sensitizer and of aftershave/perfume samples resulted in a strong degradation. Photooxygenation was identified as the major degradation reaction for all three trials. OTNE photooxidation products were characterized by LC-high resolution mass spectrometry (LC-HRMS) and by high-performance thin-layer chromatography (HPTLC) after derivatization with titanium ethoxide and nitrobenzyl pyridine. Both HPTLC and HRMS data indicate that OTNE hydroperoxides are formed during irradiation.