SFX may refer to:
- Special effect(s), illusions used in film, television and entertainment
- Sound effect, artificially created or enhanced sounds
- Onomatopoeias in comics are referred to as "SFX" or "sound effects"
- SFX (magazine), a science fiction magazine
- SFX (Science Fiction Expo), a science fiction convention in Toronto, Canada
- SFX (group), a psychedelic trance musical band that changed their name to Astral Projection
- SFX (software), an OpenURL link server
- SFX Entertainment, a music promotion company owned by Live Nation
- S·F·X, a 1984 album by Japanese electronic artist Haruomi Hosono
- Self-extracting archive (SFX), a compressed file with an embedded executable to decompress itself
- Spread Firefox, a campaign to encourage the use of Mozilla Firefox
- SquirrelFish Extreme, a JavaScript engine for WebKit
- Ilford SFX, a photographic film
- Super FX, a coprocessor chip used in some Super Nintendo video game cartridges
- SFX (PSU) a form factor for a power supply unit for PCs