In this work, surface modification of ZnO nanowires (NWs) with oleic acid is reported. ZnO NWs were synthesized in a customized chemical vapor deposition furnace and were characterized with scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy. Raman and infrared spectroscopies were used to determine that oleic acid modifies the ZnO NW surface with the carboxylate group attached to the surface. The study of the surface chemistry of ZnO NWs provides information about the class of compounds that modify ZnO NWs. This information will assist in tailoring the interface of NWs with appropriate compounds for fabricating nanosensors with high selectivity.