An anti-rotation system for use in retaining a threaded connection between a pin and a box. The anti-rotation system includes a key that sets in a recess formed in one of the box or pin. The key is selectively in contact with one of the other of the box or pin, and is activated when the threaded connection begins to decouple. The key is profiled and operates in a cam like fashion to wedge itself between the box and pin when these members begin to decouple and prevents further relative rotation.