| Acronym | Meaning |
| MA | Mom alert Master of Arts |
| MAAB | Male-Assigned At Birth |
| MAC | Media Access Control Macintosh |
| MADD | Mothers Against Drunk Driving |
| MAPOTI | Most Annoying People On The Internet |
| MAS | Mildly Amused Smirk |
| MAW | Might As Well |
| MAWOY | May Angels Watch Over You |
| MBA | Masters of Business Association Married But Available |
| MBD | My Bad Dudes |
| MBF | My Best Friend |
| MBFAM | My Brother From Another Mother |
| MBM | Married Black Male |
| MBN | Must Be Nice |
| MBO | Must Be Off Management Buy-Out |
| MBPS | MegaBits/Bytes Per Second |
| MBR | Master Boot Record |
| MBT | Masai Barefoot Technology (trainers) |
| MBW | Married Black Woman |
| MC | Master of Ceremonies |
| MCL | Much Clown Love |
| MCM | Man Crush Monday |
| MCP | Male Chauvanist Pig |
| MCR | My Chemical Romance (band) |
| MCW | Man Crush Wednesday |
| MDF | Medium Density Fiberboard |
| MDK | Murder Death Kill |
| MDR | Mort De Rire ( in French) |
| MDW | Memorial Day Weekend |
| MEGO | My Eyes Glazed Over |
| MFC | Mildly Fat Chick Microsoft Foundation Classes |
| MFEO | Made For Each Other |
| MFG | Mit Freundlichen Gruessen (German) |
| MFL | Marked For Later |
| MFW | My Face When … |
| MGBY | May God Bless You |
| MGD | Miller Genuine Draft |
| MGK | Machine Gun Kelly |
| MGM | Male Genital Mutilation |
| MGMT | The Management (band) |
| MGO | Metal Gear Online (game) |
| MGS | Metal Gear Solid (game) |
| MH | Map Hack |
| MHBFY | My Heart Bleeds For You |
| MHO | My Honest Opinion |
| MHOTY | My Hat’s Off To You |
| MHR | Many Happy Returns |
| MI6 | Military Intelligence Service 6 |
| MIA | Missing In Action |
| MIB | Men In Black Mint In Box |
| MIDI | Musical Instrument Digital Interface |
| MIGA | Make It Go Away |
| MIH | Make It Happen |
| MIHOP | Made It Happen on Purpose |
| MIL | Mother In Law |
| MIMO | Multiple Input Multiple Output |
| MIP | Minor In Possession |
| MIPS | Million Instructions Per Second |
| MIRL | Meet In Real Life |
| MISB | Mint (condition) In Sealed Box |
| MISO | My Internet Shut Off |
| MJ | Michael Jackson Michael Jordan Marijuana |
| MLAS | My Lips Are Sealed |
| MLB | Major League Baseball |
| MLG | Major League Gaming |
| MLIA | My Life Is Average |
| MLIB | My Life Is Bro |
| MLIG | My Life Is Great/Good |
| MLIM | My Life Is Magic |
| MLM | Multi-Level Marketing Middle finger (mlm) |
| MLP | My Little Pony |
| MLS | My Life Sucks |
| MLTR | Multiple Long Term Relationships |
| MLYP | Much Like Your Post |
| MM | Married Man |
| MM2 | Message Mode 2 ( ) |
| MMA | Meet Me At… |
| MMAMP | Meet Me At My Place |
| MMAO | Make Me An Offer |
| MMC | MultiMedia Card |
| MMD | Make My Day |
| MMH | Meet Me Halfway |
| MMI | Me Myself and I |
| MML | Made Me Laugh |
| MMOFPS | Massively Multiplayer Online First Person Shooter |
| MMORPG | Massively Multiplayer Online Role Playing Game |
| MMS | Multimedia Messaging Service |
| MMT | Makes Me Think |
| MMV | Mileage May Vary |
| MNC | Mobile Network Code |
| MNF | Monday Night Football |
| MNT | Maybe Next Time |
| MO | Modus Operandi (method of operation) |
| MOAB | Mother of All Bombs Massive Ordnance Air Blast |
| MOAM | Man On A Mission |
| MOAS | Mother Of All Secrets |
| MOBA | Multiplayer Online Battle Arena |
| MOC | Marriage Of Convenience My Own Creation |
| MOH | My Other Half |
| MOL | More Or Less |
| MOO | Matter of Opinion My Own Opinion |
| MOPO | Master Of the Painfully Obvious |
| MOQ | Minimum Order Quantity |
| MOS | Mom Over Shoulder |
| MOT | Ministry Of Transport test for car safety |
| MOTB | Mother Of The Bride |
| MOTD | Message Of The Day Match Of The Day |
| MOTKU | Master Of The Known Universe |
| MOTO | Master Of The Obvious |
| MOTWYW | Make Of That What You Will |
| MOU | Memorandum Of Understanding |
| MP | Military Police Member of Parliament |
| MPA | Music Publishers’ Association |
| MPAA | Motion Picture Assosciation of America |
| MPE | My Point Exactly |
| MPEG | Moving Picture Experts Group Audio/visual file format |
| MPG | Miles Per Gallon |
| MPH | Miles Per Hour |
| MPO | My Personal Opinion |
| MPOG | Multiplayer Online Game |
| MPUA | Master Pick Up Artist |
| MPV | Multi-Purpose Vehicle |
| MR | Mentally Retarded |
| MRE | Meal, Ready to Eat |
| MRI | Magnetic Resonance Imaging |
| MRP | Manufacturer’s Recommended Price |
| MRW | My Reaction When… |
| MSDN | Microsoft Developer Network |
| MSDOS | Microsoft Disk Operating System |
| MS-DOS | Microsoft Disk Operating System |
| MSF | Male Seeking Female |
| MSFAM | My Sister From Another Mister |
| MSG | Message Monosodium Glutamate |
| MSI | Mindless Self Indulgence (band) |
| MSM | Mainstream Media |
| MSRP | Manufacturer’s Suggested Retail Price |
| MST | Mystery Science Theater |
| MTA | More Than Anything |
| MTBF | Mean Time Between Failures (reliability) |
| MTBMW | May The Best Man Win |
| MTC | More To Come |
| MTD | Month To Date |
| MTE | My Thoughts Exactly |
| MTF | Male To Female |
| MTFBWY | May The Force Be With You |
| MTG | Magic: The Gathering (game) |
| MTLBWY | May The Lord Be With You |
| MTO | Media Take Out (gossip website) |
| MTUK | More Than You Know |
| MTV | Music Television |
| MTW | Mum’s the Word |
| MTYK | More Than You Know |
| MU | Multi User |
| MUA | Make-Up Alley (website) |
| MUD | Multi-User Dungeon, |
| MUNG | Mash Until No Good |
| MVA | Motor Vehicle Accident |
| MVP | Most Valuable Player |
| MW2 | Modern Warfare 2 (game) |
| MW3 | Modern Warfare 3 (game) |
| MWC | Married With Children |
| MWF | Married White Female |
| MWI | Mad With It (drunk) |
| MWM | Married White Male |
| MWPP | Moony, Wormtail, Padfoot, and Prongs (Harry Potter) |
| MY | Miss You |
| MYB | Mind Your Business |
| MYCH | Maybe You Can Help |
| MYF | Miss Your Face |
| MYGGWY | May Your God Go With You |
| MYL | Miss You Loads |
| MYMP | Make Your Mama Proud |
| MYOB | Mind Your Own Business |
| MYODB | Mind Your Own Damn Business |
| MYSM | Miss You So Much |
| MYT | Meet You There |