The electron scattering at the surfaces of an Au film vacuum deposited on Bi2O3 is analyzed as a function of film thickness using the Fuchs‐Sondheimer theory modified to allow the determination of the scattering parameters separately at each of the film surfaces. The scattering at the air‐Au interface becomes less specular as Au‐film thickness increases. In the analysis the assumption is made that the scattering parameter at the Au-Bi2O3 interface is unaffected by variation in Au‐film thickness. The justification for this assumption is the strong influence of the Bi2O3 on the growth characteristic of the Au film. It is known that a given Au‐film thickness will become continuous when deposited on Bi2O3, whereas a film of that same thickness would be discontinuous deposited on bare glass or quartz.