RSX can mean any of the following:
- RS:X, an Olympic windsurfing class
- RSX Energy, an oil and gas exploration and production company based in Calgary, Alberta, Canada
- RSX, a RISC-CPU from Encore Computer
- RSX-11, a family of operating systems developed by Digital Equipment Corporation
- Acura RSX (aka Honda Integra DC5), a sport compact/hatchback car made by Acura
- RSX 'Reality Synthesizer', a graphics chip created for the PlayStation 3 video game console
- Resident System Extension, part of CP/M Plus