SD
- Democratic Left (Italy)
- Democratic Party (Poland)
- Eswatini
- Major League Baseball
- Pierre Auger Observatory
- RECIST
- SD card
- SD radar
- SD1 (disambiguation)
- San Diego
- San Diego Padres
- Sekolah Dasar
- Serbian Right
- Service design
- Shandong
- Sicherheitsdienst
- Sindhi language
- Sisters of the Destitute
- Social Democrats (Slovenia)
- Software Distributor
- Solidarity (Brazil)
- South Dakota
- Southern Cross Decoration
- Spasmodic dysphonia
- Spiral Dynamics
- Stable Diffusion
- Standard deviation
- Standard-definition television
- Storm Data
- Subdwarf
- Sudan
- Sudan Airways
- Super D (cycling)
- Super Density Disc
- Super deformed
- Sweden Democrats
- Swiss Democrats
- System dynamics