The effect of hydrostatic pressure on the interface state density and Schottky barrier diode parameters such as ideality factor and barrier height obtained from the current–voltage (I–V) characteristics of Au/n-InP Schottky diodes was studied. It is shown that the ideality factor and the barrier height values of Au/n-InP diodes are in the range 2.36–1.93 and 0.546–0.579 eV for the 0.0–5.0 kbar pressure interval at room temperature, respectively. We have seen that the barrier height for Au/n-InP Schottky diodes has a linear pressure coefficient of 6.87 meV/kbar (=68.7meV/GPa), approximately equal to that found for the band gap of InP. This means that the Fermi level is a reference level which is pinned to the conduction band minimum as a function of pressure. On the other hand, the interface state density decreases with increasing hydrostatic pressure due to the rectifying properties of the diode.