A universal tuning knob for stringed instruments is presented. The invention consists of a knob with an elongated and threaded cylindrical shaft. The shaft includes a lumen sized to receive the machine head post of any stringed instrument. The outside perimeter of the knob is configured for grip. The threaded cylindrical shaft includes a slot on its side wall to receive and retain a bushing. The bushing includes a second slot that can be notched (i.e. sized) to fit and lock the machine head post of any stringed instrument. A sleeve lock with internal threads is threaded onto the threaded cylindrical shaft of the knob thereby retaining the bushing. An optional second lumen on the head of the knob is configured to receive a mounting screw.