GBM may refer to:
- Game Boy Micro, a portable video game system from Nintendo
- geometric Brownian motion, used in mathematical modelling of some phenomena in financial markets
- George B. McClellan, a Union general during the American Civil War known for organizing the Army of the Potomac
- GLAST Burst Monitor, renamed Gamma-ray Burst Monitor, an instrument aboard the Fermi Gamma-ray Space Telescope
- Global Banking & Markets, a business in the Royal Bank of Scotland group
- gradient boosting, a machine learning technique
- Grand Bauhinia Medal, an honour in Hong Kong
- Greater Britain Movement, a far right group
- Isle of Man's international vehicle license plate code
- Great Bowel Movement, a social awareness movement for Crohn's Disease and Colitis
Read more about GBM: Medicine