IGM may refer to:
- IG Metall, the predominant German metalworkers' union
- IGM Financial, Canada's largest manager and distributor of mutual funds and other managed asset products
- Immunoglobulin M, the primary antibody against A and B antigens on red blood cells
- Institut Gaspard Monge, a research institute at the University of Marne la Vallée
- International grandmaster, a chess ranking
- Intergalactic medium
- Intersex genital mutilation (or intersex genital modification)
- Intragroup medium
- Kingman Airport (Arizona) (IATA Code: IGM)