By the X-ray diffraction method, textures in high-purity rare-earth Tb-Gd system alloys (99.99 mass % purity) are examined upon crystallization and additional 50% plastic deformation by swaging. It is established, that when passing on the concentration scale from pure terbium to pure gadolinium, the role of basal slip is reduced and prismatic slip is enhanced. It is concluded, that one of the factors determining the type of texture formation in the Tb-Gd system is stacking fault energy.