MMS
- M.M.S.
- MMS-class minesweeper
- Machinist's mate
- Magnetospheric Multiscale Mission
- Manufacturing Message Specification
- Marshall Middle School (Pittsburgh)
- Massachusetts Medical Society
- Master of Management
- Maximin share
- Mayo Clinic School of Medicine
- Medical Mission Sisters
- Methodist Missionary Society of Australasia
- Methyl methanesulfonate
- Metro Manila Subway
- Metropolitan mountaineering society
- Microsoft Media Server
- Minerals Management Service
- Miracle Mineral Supplement
- Modern Montessori School
- Moment magnitude scale
- Movimento Mérito e Sociedade
- Multimedia Messaging Service
- Multiscale Modeling and Simulation
- North Wildwood School District