Abstract: A golf swing practice device (10) having an elongate flat guide member (11) defining a lineal guide edge (26) adapted to be placed on the ground adjacent to a golf ball (25) to be struck with the lineal guide edge (26) extending parallel to the desired and intended line-of-flight (28, 39) of the golf ball (25); an upstanding L-shaped guide element (14) having a vertical leg (15) and a horizontal leg (16) defining a swing plane stabilizer; a fastening device (13, 20) extending through an elongate vertical slot (19) formed in the guide member (11) and through the horizontal leg (16) formed on the swing plane stabilizer (14) so as to separably, but fixedly, secure the guide element (14) to the guide member (11) in any desired adjustable position along the length of the slot (19); and, a phantom tee (21) separably coupled to the guide member (11) adapted to be position forward of the golf ball (25 ) along the intended line-of-flight (28, 39) thereof for defining the intended bottom of the golfer's (29) swing when