The abbreviation MGB may refer to:
- Mathematical Gymnasium Belgrade, special school, elementary and high school, for gifted in areas of mathematics, physics, and ICT, under University of Belgrade umbrella. Ranked number one in International Science Olympiads and international competitions in math, physics, and informatics.
- MG MGB, a sports car produced by the British Motor Corporation and its successors in the 1960s and 1970s and early 80's.
- The 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.
- Mini-Gastric Bypass, a specialized gastric bypass procedure developed by Dr. Robert Rutledge.
- Ministry for State Security (USSR) (Ministerstvo Gosudarstvennoi Bezopasnosti), a predecessor of the KGB (secret police).
- A wheelie bin, also known as a mobile garbage bin.
- Motor Gun Boat, a fast attack boat with weapons based around cannons and guns, as opposed to the Motor Torpedo Boat.
- Mutual gains bargaining
- Mount Gambier Airport, an airport servicing the Mount Gambier region which uses the IATA code MGB.
- Magandang Gabi, Bayan, a Philippine Documentary TV program.