A peel test is a useful method for comparing the behavior of various adherends and adhesives. An exact analysis of the mechanics of the peel test would be of great help in the interpretation of test results in terms of the bulk properties of the materials, and of the failure mechanism of the bond. The existing theories of peeling apply to elastic peel films, very thin elastic or viscoelastic adhesive, and a rigid substrate. In many applications the film is metallic, stressed beyond its elastic range; the elasticity of the substrate is often similar to that of the adhesive; and the adhesive may be quite thick compared to the film, or may be wholly absent as in electroplated components. In this paper, the effects of non-elastic behavior of the film are analyzed. Results from the use of computer programs that incorporate an analytical model of steady state peeling are presented and compared with experimental data.