This article describes the effect of In2O3 doping on the luminance of ZnGa2O4 phosphor. The crystalline properties, photoluminescence (PL), cathodoluminescence (CE), and resistivity of the In2O3-doped ZnGa2O4 phosphor will be discussed. The PL wavelength of In2O3-doped ZnGa2O4 phosphor is centered at 4020 Angstrom; it is insensitive to the In2O3 doping. However, the PL intensity depends on the In2O3 concentration, and it initially increased, then decreased with the concentration of In2O3. The CL intensity of phosphor also depends on the concentration of the In2O3 dopant. The maximum CL intensity of the In2O3-doped ZnGa2O4 phosphor is obtained at an In2O3 concentration of 12 wt%. At this doping level, a minimum resistivity of 1.4 M Omegam of phosphor is obtained. In conclusion, the luminance of ZnGa2O4 phosphor is enhanced by In2O3 doping.