Abstract: The present invention describes a firearm lock 20 having a combination lock 20 for firearms 10 which uses four tumbler locking mechanisms 22, 24, 26 and 28 connected to the firing trigger 16 mechanism by way of a trigger deactuator rod 38. The trigger 16 firing mechanism is disabled until the four or more tumblers 22, 24, 26 and 28 of the combination lock 20 are positioned in such a way as to allow a preselected combination or pin number on the tumblers to communicate with a tumbler pin 44, 46, 48 and 50 attached to the trigger deactuator rod 38. When the numbers of the disk tumblers 22, 24, 26 and 28 are properly entered, the tumbler pins 44, 46, 48 and 50 of the trigger deactuator rod 38 will seat in a single hole and thereby allow the trigger 16 firing mechanism to be actuated. If the wrong number of the combination is entered, the tumbler pin will contact a false hole after traveling only a short distance thereby locking and preventing the trigger mechanism from firing.