The failure of interface elements is typically based on interactive mixed mode criteria for both initiation and propagation of damage. The effect of tensile through-thickness stress is normally taken into account in combination with interlaminar shear stress. When the through-thickness stress is compressive, however, its effect is usually ignored and the failure of interface elements is considered to be pure mode II. Experiments on single-lap, cut-ply and dropped-ply specimens however show that the compressive through-thickness stress can greatly increase the delamination failure stress and cannot be simply neglected.The influence of compressive stress on mode II damage evolution is investigated numerically based on the cut-ply and dropped-ply experiments. A new interfacial failure model with modified failure initiation and propagation criteria is proposed to take the effect of compression on matrix shear strength and mode II critical fracture energy, G IIC , into account. The new model uses one independently determined parameter to relate the compression to the increase in interlaminar shear strength and G IIC . With the new failure criterion applied, two types of cut-ply models and two types of dropped-ply models, using the same input parameter, all produce excellent correlation with experimental delamination stresses. As a validation case the single-lap model was run with the new criterion and the same input parameters and this also achieves very good correlation with the experimental failure stress.