The abbreviation MGB may refer to: 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. Mini-Gastric Bypass, a specialized gastric bypass procedure developed by Dr. Robert Rutledge. Ministry for State Security (USSR) (Mini… (More on Mgb)