A stuffing box lubrication system for oilfield pumping units automatically delivers to the stuffing box, at specified time intervals, a precise volume of lubricant. The stuffing box lubrication system has a grease reservoir, a pump, a controller, a high pressure hose and grease fitting, and a stuffing box which receives the grease. In situations where the stuffing box in use is not equipped with a ported inlet for receiving the grease, the present invention may further include a stuffing box adapter, having a ported inlet, where the stuffing box adapter couples with the stuffing box.