A light emitting module is attached to one of a pair of separable U-shaped metal clamps that can fit around a weapon trigger guard. The clamps have recesses for retaining elastomeric inserts which contact the trigger guard. The inserts are of inexpensive glass-filled molded plastic rather than machined steel so that a greater variety can be provided at low cost and little value is lost by discarding those not needed for a particular weapon. The greater variety provides a better fit with little or no custom shaping and the elastomeric inserts are much easier to shape if an unusually contoured trigger guard is encountered. The electrical cord running to the on/off switch for the module emerges from the module in fixed relationship to the clamps and need not be removed to change the module batteries. A trigger guard mountable laser sight that is more resistant to shock and requires less ongoing adjustment to maintain light beam and boresight coincidence is obtained.