M3
- 105 mm Howitzer M3
- 1N4003
- 37 mm Gun M3
- 3M (disambiguation)
- 90 mm Gun M1/M2/M3
- ABSA - Aerolinhas Brasileiras
- ATC code M03
- Apple M3
- BMW M3
- BYD M3
- Benelli M3 Super 90
- Bernie Marsden
- Bisu M3
- Carl Gustaf 8.4cm recoilless rifle
- DJI Matrice
- DJI Mavic
- Dongfeng Fengxing Lingzhi
- EastLink (Melbourne)
- Eastern Freeway (Melbourne)
- Haima M3
- Highway M03 (Ukraine)
- ISO metric screw thread
- Intel m3
- JAC Refine M3
- Jalan Datuk Wira Poh Ah Tiam
- Korg M3
- LCDR M3 class
- Leica M3
- Line M3 (Budapest Metro)
- List of highways numbered 3
- List of mine warfare vessels of the Swedish Navy
- M-3 (Michigan highway)
- M.3 (computing)
- M1/M3 (railcar)
- M1903 (disambiguation)
- M3 (Canadian TV channel)
- M3 (Cape Town)
- M3 (Copenhagen)
- M3 (East London)
- M3 (Hungarian TV channel)
- M3 (Istanbul Metro)
- M3 (New York City bus)
- M3 (Port Elizabeth)
- M3 (Pretoria)
- M3 (album)
- M3 (band)
- M3 (economics)
- M3 (email client)
- M3 (hieroglyph)
- M3 (magazine)
- M3 20mm cannon
- M3 Amphibious Rig
- M3 Bradley
- M3 Gun Motor Carriage
- M3 Lee
- M3 Milton–City Centre
- M3 Music Card
- M3 Ram
- M3 Records
- M3 Scout Car
- M3 Stuart
- M3 adapter
- M3 fighting knife
- M3 half-track
- M3 highway (Russia)
- M3 machine gun
- M3 motorway (disambiguation)
- M3 road (Malawi)
- M3 road (Zambia)
- M3 submachine gun
- M3 tripod
- M4 (computer language)
- MLBB M3 World Championship
- MMM (disambiguation)
- Major third
- Major thirds tuning
- Messier 3
- Micky Moody
- Milan Metro Line 3
- Miles M.3 Falcon
- Minor third
- Modula-3
- Moon Mineralogy Mapper
- Muscarinic acetylcholine receptor M3
- Music Media-Mix Market
- Neil Murray (British musician)
- Nintendo DS and 3DS storage devices
- Panhard M3
- Roosevelt Roads Naval Station
- Route M-3 (MTA Maryland)
- Sri Lanka Railways M3
- The Company of Snakes
- The M-3 (My Mood Monitor) Screen
- Vicente Alcazar
- XPeng Mona M03