Submillimeter laser action has been achieved in ammonia by Stark shifting vibrational absorption lines into resonance with a CO2laser pump. In two of the three observed cases the absorption line was between states of the same parity, i.e., forbidden in the absence of the applied Stark field. Stark tuning of a vibrational absorption into resonance with a pump laser line is a general technique which should greatly increase the number of stable cw submillimeter lines available at milliwatt power levels.