The relationship between the processes of twinning in ε-martensite plates and deformation processes in surrounding austenite has been considered. Four variants of the relation between the {102}ε twins and the {111}γ plane of austenite 'intersecting' the habit plane of the ε-martensite plate were found experimentally. The differences in the probability of twinning observed for these variants are explained. The factor that controls the formation of {101}ε twins was revealed. The role of an external load and of the steel microstructure in the twinning of ε martensite was estimated.