RIR
- Autonomous system (Internet)
- IP address
- React, Include, Recycle
- Regional Internet registry
- Rhode Island Red
- Richmond International Raceway
- Rio de Janeiro
- Riverside International Raceway
- Rock in Rio
- Royal Irish Rangers
- Royal Irish Regiment (1684–1922)
- Royal Irish Regiment (1992)
- Royal Irish Rifles
- Rush (band)
- Rush in Rio
- Steve Vai