GCM can refer to:
Global climate model (also known as a general circulation model), describes climate behavior by integrating a variety of fluid-dynamical, chemical, or even biological equations
Owen Roberts International Airport, in Grand Cayman, Cayman Islands - IATA airport code
Galois/Counter Mode (GCM Mode), a mode of operation for cryptographic block ciphers
Great Commission Ministries, a not-for-profit Christian evangelistic organization
Gift causa mortis, a gift that takes effect on the death of the donor
Gross Combination Mass, the maximum combined mass of a motor vehicle and its trailers
Gentle Christian Mothers, an online community for Christian mothers who practice attachment parenting
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