A simple physical model that predicts charge accumulation at the dielectric interface of metal‐nitride‐oxide‐silicon (MNOS) structures is proposed and verified experimentally. The model is based on the presence of steady‐state current flow in the dielectric structure. Interface‐charge accumulation is shown to be determined by the requirement for continuity of current through the structure under steady‐state conditions. Continuity of current is established by accumulation of either positive or negative charge for a given polarity of charging voltage, depending on the relative current‐field characteristics of the silicon nitride and silicon dioxide layers. Due to the exponential nature of the current‐field characteristics, the time required to reach steady state is a strong function of the applied charging voltage. This leads to the observed charge storage property of MNOS devices. The hysteresis characteristic observed in MNOS structures is shown to be time‐dependent with a tendency to merge into a single‐valued dependence of accumulated charge on charging voltage as the steady‐state condition is approached. The validity of the theoretical model for both steady‐state and transient behavior is confirmed by current‐voltage, capacitance‐voltage, and turn‐on measurements of MNOS capacitors and transistors for different dielectric thickness ratios and over a wide temperature range. The underlying concept that charge accumulation establishes current continuity in a two‐layer dielectric structure should be valid, in general, for any two‐dielectric structure.