A review article is presented of the author’s work on light emission from electron tunneling junctions. The light emission arises from the radiative decay of junction surface plasmon modes excited by tunneling electrons. The coupling out of the light is assisted by roughness and resonant particle scattering schemes. As a consequence of the quantum nature of the light generation process, there is a fundamental relation between the applied voltage and the observed emission spectrum. Because of the limited tunneling electron‐surface plasmon coupling, these thin‐film light sources have photometric brightnesses of only a few foot‐Lamberts. Other avenues of research for brighter thin‐film light sources are: development of metal electrodes having a lower surface plasmon frequency excitation of electronic transitions.