GBM may refer to:
Medicine Glioblastoma multiforme, an outdated term for glioblastoma Glomerular basement membrane
Science and technology Gateway belief model, a model in psychology and the communication sciences Geometric Brownian motion, continuous stochastic process where the logarithm of a variable follows a Brownian movement, that is a Wiener process Gradient boosting, a machine learning technique Generic Buffer Management, a graphics API Gamma-ray Burst Monitor, aboard the Fermi Gamma-ray Space Telescope Game Boy Micro, a 2005 handheld game console and the last model in the Game Boy line
Other uses Grand Besançon Métropole, a French intercommunal structure GBM (League of Legends player) (born 1994), Korean video gamer Geoffrey Bwalya Mwamba (born 1959), Zambian politician Garbaharey Airport, in Somalia Garhwali language Grand Bauhinia Medal, an honour of Hong Kong Greater Britain Movement, a short-lived far-right group Green Belt Movement, a Kenyan environmental organisation