We report the formation and the optical properties of Tm, Yb-codoped ZnO nanowires (NWs) grown by sputtering-assisted metalorganic chemical vapor deposition. The growth conditions of the ZnO core NWs are optimized by changing the growth temperature and the VI/II ratio. The optimal conditions are elucidated via structural analysis by scanning electron microscopy, X-ray diffractometry, and optical characterization. The ZnO:Tm,Yb/ZnO core-shell NWs are formed by growing ZnO:Tm,Yb shells on optimized ZnO core NWs. Light emission originating from the highest (1)G(4)-H-3(6) transitions from Tm3+ ions is observed around 490 nm in ZnO:Tm,Yb/ZnO NWs due to the improved crystal quality of the ZnO host by utilizing the NW configuration.