MSD may refer to:
- Machampalayam Swaminathan Deepakh (born 1983), Indian.
- Macromolecular Structure Database, one of the services provided by the European Bioinformatics Institute
- Mahendra Singh Dhoni (born 1981), Indian cricketer
- Marine Sanitation Device
- Mars Solar Date
- Maryland School for the Deaf
- Mass spectrometric detector, a type of chromatography detector
- Mass storage device, like a USB key
- Master of Science by Dissertation, a research-led M.Sc.
- Michael S. Dukakis, the 1988 U.S. Democratic Party nominee for President of the United States
- Master Scuba Diver, a certification level in recreational Scuba diving
- Mean Shortest Distance, in the context of the PGP Web of trust
- Mean squared displacement (also: mean square displacement), a statistical measure of random motion
- Memory Stick Duo, a type of solid digital data storage device
- Merck Sharp and Dohme, aka Merck & Co., the U.S. and Canada pharmaceutical company spun off from the German Merck KGaA
- Microsoft Diagnostics, a computer diagnostic program shipped with various versions of DOS and Microsoft Windows operating systems
- Ministry of Social Development, a New Zealand government agency
- Milford School District, a school district in Milford, Delaware
- Mission Science Division, a group of scientists, research fellows and young graduates working at the European Space Agency
- Mladí sociálni demokrati or Young Social Democrats (Slovakia), a social democratic youth organization in Slovakia
- Mobile Security Deployment, the U.S. Diplomatic Security Service's Special Ops/SWAT unit
- Moscow School District in Moscow, Idaho
- Modem Sharing Device
- Moorside railway station, England National Rail station code
- Moscow Summer Time
- Motor Sports Developments, an automotive engineering company based in Milton Keynes, United Kingdom, see X25XE
- Musculoskeletal disorders
- Metro de Santo Domingo, a rapid transit system in Santo Domingo, the capital of the Dominican Republic
- MSD Super Disk, a floppy disk drive for Commodore 8-bit systems.