RTS
- Gainesville Regional Transit System
- Johor Bahru–Singapore Rapid Transit System
- Payment Services Directive
- Radio Television of Serbia
- Radio Télévision Suisse
- Radio and Television of Slovakia
- Radio teleswitch
- Radiodiffusion Télévision Sénégalaise
- Radiotelevizija Slovenija
- Rape trauma syndrome
- Rapid Transit Series
- Real Time Snickometer
- Real-time strategy
- Reclaim the Streets
- RedTeleSistema
- Reformed Theological Seminary
- Religious Tract Society
- Request to Send (disambiguation)
- Return statement
- Return to sender (disambiguation)
- Revised Trauma Score
- Rochester-Genesee Regional Transportation Authority
- Ronald Reagan Ballistic Missile Defense Test Site
- Rottnest Island Airport
- Royal Television Society
- Rubinstein–Taybi syndrome
- Runtime system
- Russian Trading System
- SES/RTS