| MRF | Madras Rubber Factory |
| MBA | Master of Business Administration |
| MLA | Member of Legislative Assembly |
| MSC | Master of Science |
| MSC | Mobile Switching Center |
| MS | Master of Surgery |
| MD | Doctor of Medicine |
| MCA | Master of Computer Application |
| MCA | Ministry of Corporate Affairs |
| MTS | Microsoft Transaction Server |
| MCB | Miniature Circuit Breaker |
| MBBS | Bachelor of Medicine, Bachelor of Surgery |
| MC | Menstrual Cycle |
| MMR | Measles Mumps and Rubella |
| MRI | Magnetic Resonance Imaging |
| MIS | Management Information System |
| MTNL | Mahanagar Telephone Nigam Limited |
| MPEG | Moving Picture Experts Group |
| MAH | Milliampere Hours |
| MCM | Mighty Car Mods / Man Crush Monday |
| MMS | Multimedia Messaging Service |
| MMS | Microsoft Media Server |
| MICR | Magnetic Ink Character Recognition |
| MFW | My Face When |
| MMW | Mark my words |
| MYOB | Mind your own business |
| MAHATET | Maharashtra Teacher Eligibility Test |
| MPTET | Madhya Pradesh Teacher Eligibility Test |
| MH SET | Maharastra State Eligibility Test |
| MCL | Medial Collateral Ligament |
| M/H | Medical History |
| MAGST Time Zone | Magadan Summer Time (Daylight Saving Time) |
| MAGT Time Zone | Magadan Time (Standard Time) |
| MART Time Zone | Marquesas Time (Standard Time) |
| MAWT Time Zone | Mawson Time (Standard Time) |
| MDT Time Zone | Mountain Daylight Time (Daylight Saving Time) |
| MHT Time Zone | Marshall Islands Time (Standard Time) |
| MMT Time Zone | Myanmar Time (Standard Time) |
| MSD Time Zone | Moscow Daylight Time (Daylight Saving Time) |
| MSK Time Zone | Moscow Standard Time (Standard Time) |
| MST Time Zone | Mountain Standard Time / Mountain Time (Standard Time) |
| MT Time Zone | Mountain Time |
| MUT Time Zone | Mauritius Time (Standard Time) |
| MVT Time Zone | Maldives Time (Standard Time) |
| MYT Time Zone | Malaysia Time (Standard Time) |
