SD may refer to:
South Dakota, United States postal abbreviation
San Diego

• The San Diego Padres, or San Diego Chargers
  Sales and Distribution, business
  SanDisk, US-based multinational corporation which designs and markets flash memory card products
  SafeDisc, a CD/DVD copy protection solution by Macrovision Corporation
  Secure Digital card, flash memory card format used in portable device, including digital cameras and handheld computers
  Self Destruct, in some video games.
  Siamese Dream, a rock music album from the band The Smashing Pumpkins
  Sicherheitsdienst, Security Police, the intelligence service of the Nazi SS
  Sindhi language
  Snare drum
  Social Democrats (Slovenia), a left-wing Slovenian political party
  Software Distributor, an HP-UX software package management system
  Standard-definition television
  Standard Deviation, statistics
  Stronnictwo Demokratyczne, a defunct Polish party
  Structured design, a computer programming concept
  Sub-Divisions of India, an administrative unit of certain states of India
  Sudan, ISO country code
  Sudan Airways, IATA airline designator
  Super Dave Osborne, an alter-ego of comedian Bob Einstein
  Super deformed, an exaggerated drawing style used in anime and manga
  Super Dollfie, a doll by Japanese company Volks
  Suppressed, a suffix placed at the end of a firearm's model name to note it is fitted with a suppressor.
  Sustainable Development, Environmental, economic and social development that meets the needs of the present without compromising the needs of future generations
  Significant digits, a method of expressing error in measurement
  SharpDevelop, a free and open source IDE for the C# Visual Basic .NET programming languages
  Snoop Dog (famous rapper)
  Scooby Doo