Light emission via inelastic tunneling (LEIT) has been observed from the metal‐insulator‐semiconductor tunnel‐junction Al‐Al2O3‐ Sn‐doped indium oxide (ITO). The spectra exhibit the bias‐voltage‐dependent upper‐frequency quantum cutoff relation. These devices were stable at room temperature for months at a time while biased to 3 V. The external quantum efficiency of this metal‐insulator‐semiconductor system is about 0.1 that of the metal‐insulator‐metal system Al‐Al2O3‐Ag. Enhancement of the light emission using silver particle resonators is also reported.