Epitaxial ZnSe/epitaxial GaAs interfaces have been formed by molecular beam expitaxy and evaluated by several techniques including capacitance‐voltage measurements. In the study reported here, the GaAs surface stoichiometry was systematically varied prior to the nucleation of ZnSe. A dramatic reduction of interface state density occurred when the GaAs epilayer was made As deficient. The resulting interface state densities of as‐grown structures are comparable to values obtained with (Al,Ga)As/GaAs interfaces.