Molecular oxygen was excited by 1.5-3.0 keV electrons. Luminescence spectra from the decay products of K-shell excitation were obtained at high resolution (bandwidth of 0.3 angstrom). With this resolution it was possible to identify and assign the observed lines to transitions from highly-excited Rydberg states of O+ and O fragments. These states appear to result from inner valence two-hole states and three-hole, one-electron states produced by Auger decay of the core hole in molecular oxygen.