MGB may refer to:

• Mass General Brigham, a Massachusetts-based integrated health care system and hospital-based research enterprise
• Mathematical Gymnasium Belgrade (Matematička Gimnazija), an elementary and high school for gifted students in Serbia
• Magandang Gabi, Bayan, a news program in the Philippines
• Matterhorn Gotthard Bahn, a railroad operating in the Swiss Alps
• Matthew Good Band, a Canadian group
• Medial geniculate nucleus, or medial geniculate body, a subnucleus of the thalamus in the brain
• Medium Girder Bridge, a modular, military bridge
• MG MGB, a sports car produced by the British Motor Corporation and its successors from 1962 to 1980
• Mines and Geosciences Bureau, a government agency in the Philippines
• Ministry for State Security (Soviet Union) (Ministerstvo Gosudarstvennoi Bezopasnosti), a predecessor of the KGB
• Motor Gun Boat, a fast attack boat armed with cannons and guns, as opposed to the Motor Torpedo Boat
• Mount Gambier Airport, an airport servicing the Mount Gambier region which uses the IATA code MGB
• Game Boy Pocket (product code MGB-001) and Game Boy Light (product code MGB-101), portable gaming devices by Nintendo