The drift in channel current of SiO2/InP metal‐insulator‐semiconductor field‐effect transistors has been calculated using a model in which electrons thermionically tunnel to a conducting layer of In2O3within the native oxide at the interface. Calculations based on this model using reasonable values for the interface parameters are in good agreement with experimental data. The model differs from previous drift models in that trapping occurs between bulklike materials and not through discrete trap levels and is based on physical evidence for the structure of the SiO2/InP interface.