The deformation behavior of stainless steel clad aluminum sheet under uniaxial tension has been investigated. The warping phenomenon have been observed and the radius of curvature decreased with increasing uniaxial strain. The warping has been analyzed by an analytical method and FEM. A difference in plastic strain ratio of component layers of the bilayer sheet gives rise to warping of the tensile specimen. The analyzed radii of curvature of the warped specimens are in good agreement with the measured data. The transverse stresses developed in the component layers have been analyzed based on the assumption of an isostrain model and by the FEM in which the warping has been taken into account. The transverse stresses calculated by the FEM are lower than those by the isostrain hypothesis due to stress relaxation by the warping. The transverse stresses are negligible compared with the longitudinal stresses. Consequently, the flow stresses of the bilayer sheet follow the rule of mixtures.