MCB or mcb may refer to:

Science and technology Marine cloud brightening Molecular and Cellular Biology, a scientific journal Monochlorobenzene, an organic solvent Miniature circuit breaker, in electrical distribution boards Manually Controlled Barriers, a type of level crossing in the UK

Organisations Mauritius Commercial Bank, the oldest and largest banking institution in Mauritius MCB Group, a financial services holding company based in Mauritius, Mauritius Commercial Bank's holding company Muslim Commercial Bank, former name of MCB Bank Limited, a network of banks in Pakistan Maidenhead Citadel Band, of The Salvation Army Methodist College Belfast, a voluntary grammar school in Belfast, Northern Ireland Muslim Council of Britain, an umbrella body for 500 mosques, schools and associations in Britain Movimiento Continental Bolivariano, Spanish name of the Bolivarian Continental Movement, a left-wing political movement in Latin America

Transport McComb (Amtrak station) (Amtrak station code), Mississippi, US Moulsecoomb railway station, a railway station in Sussex, England Other uses Janney coupler or Master Car Builders coupler, a type railroad coupling Master combat badges (or MCBs) of the United States Army MCB Tower, a skyscraper in Pakistan, owned by MCB Bank Limited

See also United States Marine Corps Bases: Marine Corps Base Quantico Marine Corps Base Camp Pendleton