Although the mechanisms of degradation are, overall, quite similar between thermoset and thermoplastic composites, thermoplastic laminates exhibit a higher ductility. Because of that, classical models developed for thermosets fail in predicting accurately the response of thermoplastic-based laminates. Here, we demonstrate that simulations based on the properties identified on isolated thermoplastics unidirectional plies, as usually done for thermosets, result in large errors. This is explained by the significant load-bearing capacity of the ply in the transverse direction that remains even after the first-ply failure, as a result of the confinement provided by adjacent plies. This effect also exists in thermosets, but it is usually limited due to the brittle nature of the resin. We are improving the mesoscale damage modeling in the off-axis direction by introducing this confinement effect in an original way. We are using a pragmatic approach consisting of separating the progressive damage into two parts called the “diffuse damage regime” and the “transverse-cracking regime”, which we describe by two distinct damage parameters. We show that the proposed method accurately predicts the nonlinear damage behavior of the off-axis laminates, and is a viable path to tailor the classical mesoscale damage model to glass fiber-reinforced thermoplastic composites.