The optimum use of composite laminates involves predicting both first-ply-failure (FPF) and the subsequent behavior of the laminate. Several theories have been proposed to model the behavior of a ply after it fails. Three of these theories are examined here. They include modeling the lamina behavior as elastic-perfectly plastic; as a strain hardening material, as a material which unloads through a negative tangent modulus. These three methods are used to predict the ultimate strength of various laminates. Results are compared to experimental results. Although none of these approaches is totally accurate, the elastic-perfectly plastic model seems to give the best results.