The effect of 10Mrad γ-ray exposure on the interface and transport properties of Au/n-GaP Schottky diode is studied in the 220–400K temperature range. There is significant alteration in the interface and defect state density after irradiation. The Arrhenius plot of σac shows the presence of both shallow and deep trap states corresponding to activation energies 0.073eV and 0.21eV respectively. The influence of additional defects is reflected in the charge transport mechanism at low temperature regimes, where tunneling mechanisms are observed. The perceived transport and capacitance/conductance properties are ascribed due to further interfacial and deep defect state formation upon gamma irradiation.