IRG may stand for:
IATA airport code for Lockhart River Airport Ideographic Research Group on coded Han character sets Intelligent Robotics Group International Resources Group, a professional services firm Iranian Revolutionary Guard International Ratings Group, a credit ratings agency Interest rate guarantee, a financial instrument Island Reggae Greats Immunity Related Guanosine Triphosphatases (IRGs)
See also Satellite IRG, the Satellite Interference Reduction Group