A yarn false twisting apparatus and method is disclosed which comprises a pair of friction discs, with one of the discs being thin and flexible, and a pressure applying member for biasing the flexible disc toward the other disc locally at the twisting zone. The discs and pressure applying member are mounted to permit selective movement whereby the ratio of twist to yarn speed may be varied, and to achieve a desired twist in the advancing yarn. The biasing force of the pressure applying member is also adjustable, to achieve an essentially slipless operation by assuring that the torque exerted by the discs exceeds the natural restoring torque of the yarn.