A batter swing training harness and associated kit including a belt adapted to being affixed about a wearer's waist, a vertical portion extending downwardly from the belt and terminating in a looped portion adapted to being affixed about the wearer's upper leg and a first pair elastic bands extending from vertically spaced locations of the belt and vertical portion. A second individual elastic band extends from a further location of the belt. Each of the first pair of bands and the second individual band terminate in a ring adapted to being slidably supported upon a stem extending from a knob end of a bat. The harness controls a motion of the bat during each of a backswing and forward follow through to correct flaws in the batters swing, such resulting in the rings detaching either prematurely from the stem prior to completion of the swing to instruct incorrect positioning of the bat, or detaching from the stem during the forward follow through of a correct swing in order to allow the user to complete the swing.