Abstract: A golf swing training device has a compact device housing to be worn at the waist of a user on one hip which contains an inertial mass acceleration sensor for detecting when the user has moved the hip in a weight shift exceeding a given threshold level and for producing a sound output indicative of a correct weight shift for a golf swing. In one embodiment, the housing is a cylindrical tube, the sensor is a weighted metal ball held by a given retaining force of a magnet at one end of the tube, and the sound is produced by the ball striking a stop wall at the opposite end. When the user completes a hip turn and decelerates to a finish, the weighted ball travels back to the retaining end of the tube and produces a second sound which indicates correct completion of the golf swing. The device housing may have a fastener strip to allow it to be worn at an angle to vary the threshold weight shift force required.