Abstract: An improved orthodontic bracket for mounting on the inside surface or lingual of a tooth having an upwardly opening longitudinal channel for receiving an arch wire therein. The bracket includes a one-piece body having a locking groove formed in a front wall. A locking pin is rotatably mounted in a key-hole shaped opening formed in the body and is removable therefrom for replacement if it becomes damaged. The locking pin has a locking plate at one end of a shaft which is engageable in the locking groove of the body wall to secure an arch wire in the channel. A locking tab is mounted on the other end of the shaft and moves along a ramped surface formed in a recess for securing the locking plate in the locking groove. Rotation of the locking pin 180.degree. moves the locking plate between an arch wire retaining or locked position and an arch wire receiving or unlocked position. Rotation of the pin 90.degree.