SX may refer to:
- An abbreviation for Supercross, a form of off-road motorcycle racing held in outdoor and indoor stadia.
- SX News, a gay and lesbian newspaper in Sydney, Australia
- Parallax SX, a range of micro-controllers made by Ubicom
- 1000BASE-SX, a fiber optic gigabit Ethernet standard
- Skybus Airlines's IATA airline code
- SX, the aircraft registration prefix for Greek aircraft
- Sx, a medical shorthand for symptoms
- Single word eXternal, in the context of 386SX and 486SX CPUs
- Sx or sx, is a digraph in the Esperanto x-system orthography, representing the consonant sound, normally spelled as Ŝ or ŝ in the Esperanto alphabet