A microstructure-based hardening model that accounts for the dislocation reversal-related mechanisms and the cut-through effect is extended to HCP metals. This model, which is embedded in the visco-plastic self-consistent (VPSC) framework, is applied in this work to predict the mechanical response of Zn alloy during forward–reverse simple shear loading. The predicted mechanical behavior and texture evolution during pre-loading and reloading are in good agreement with experimental observations. The change in hardening behavior after reloading is well reproduced by this model. The contributions of the different mechanisms are also analyzed.