Spacecraft observations of the seven innermost planets suggest that lightning is present on all planets with dense atmospheres. Thus lightning may be expected to occur on Neptune as well. Based on the level of lightning activity observed on Jupiter and on the assumption that the lightning energy dissipation rates is a constant fraction of dissipation rate of the convective energy, the lightning rate on Neptune is estimated to be 1/19 that observed on Jupiter. It is predicted that approximately 60 events should be recorded by the Voyager imager during its search of the nightside of Neptune.