Transient capacitance measurements have been performed on Schottky barriers onn‐GaAs containing the deep electron trap associated with oxygen, as a function of hydrostatic pressure. It is found that the oxygen level separates from the conduction band at a linear rate of 3.8±0.3 meV/kbar. From a comparison with published optical data we conclude that most of this variation comes from a pressure‐dependent Frank‐Condon shift and that the unoccupied level separates very little from the valence band.