Electron temperature measurements in the ionized xenon gas downstream of a shock front are obtained using brightness observations of the XeII 5292‐Å line. The results show good agreement with previous measurements obtained using a two line intensity ratio technique. A theoretical model of the shock structure is developed which considers nonequilibrium collisional and continuum radiative transitions. The theoretical calculations agree qualitatively with the experimental observations and indicate the paramount importance of radiative heating of the electron gas within that portion of the shock structure which is otherwise dominated by elastic and inelastic electron‐heavy particle collisions. The theoretical calculations also provide a detailed time history of the populations of the first four excited levels of XeII and indicate that the higher excited levels may justifiably be assumed in equilibrium with each other in a Boltzmann sense at the local electron temperature. Considered are shock velocities between 6.0 and 10.0 km/sec at an upstream pressure of 0.1 Torr.