The temperature dependence of the electronic contribution to the nonadiabatic electron transfer rate constant (k(ET)) at metal electrodes is discussed. It is found in these calculations that this contribution is proportional to the absolute temperature T. A simple interpretation is given. We also consider the nonadiabatic rate constant for electron transfer at a semiconductor electrode. Under conditions for the maximum rate constant, the electronic contribution is also estimated to be proportional to T, but for different reasons than in the case of metals (Boltzmann statistics and transfer at the conduction band edge for the semiconductor versus Fermi-Dirac statistics and transfer at the Fermi level, which is far from the band edge, of the metal).