Abstract: A glad hand locking device featuring a mounting bracket mountable atop the glad hand mating plate of a base glad hand via bolts; a pivot arm pivotally attached to the mounting bracket, the pivot arm can pivot between an up position and a down position wherein the second end of the pivot arm is pushed downwardly past the mounting bracket, the pivot arm is biased in the up position caused by a tension spring extending from the first end of the pivot arm to the first end of the mounting bracket; and a latch disposed on the second end of the pivot arm, wherein when the mating glad hand is mated atop the base glad hand, the pivot arm can be pushed to the down position such that the latch can snugly engage the tab of the mating glad hand.