The effect of deformation temperature and strain rate (collectively described by the Zener-Hollomon parameter Z) on the deformation mechanism and texture formation of the metastable β-titanium alloy Ti5321 across the β-transus temperature during hot-compression was investigated by electron backscatter diffraction. In the β-phase field, it is found that the deformation behavior and texture formation varies depending on Z. With decreasing Z dynamic recovery and dynamic recrystallization become more and more important. The activation energy for steady state deformation is 240 kJ/mol and 370 kJ/mol in the β- and (α + β)-phase field, respectively. The texture developed is a<100> <111> double-fiber with<100>dominating at all deformation conditions. The<111> fiber gets more prominent with increasing Z suggesting that it is mainly related to deformation. Flow softening behavior of Ti5321 is associated with dynamic globularization of the α-phase and promotion of β-grain formation by continuous dynamic recrystallization.