Models have been developed and applied to predict the evolution of microstructure and texture during the thermomechanical processing of alpha/beta titanium alloys in both the alpha/beta and beta phase fields.  The present talk focuses specifically on microstructure models for alpha/beta processing of Ti-6Al-4V. This includes methods to describe static and dynamic coarsening of colony and equiaxed alpha, static and dynamic spheroidization of colony alpha, and the growth of primary alpha and formation of secondary alpha during cool-down following final alpha-beta heat treatment. Many of the models are based on quantitative descriptions of diffusional processes that lead to a reduction of alpha-beta interface area (e.g., coarsening and spheroidization) or a reduction of beta matrix supersaturation (e.g., microstructure evolution during cool-down). The suite of analytical and numerical tools will be summarized for these processes. The importance of appropriate material parameters (e.g., diffusivity, alpha/beta interface energies) for assessing the accuracy of the models will be underscored. The validation of models under both laboratory and production-scale conditions will be summarized.