RDD
- Adygeya Airlines
- Apache Spark
- Clipper (programming language)
- Radar detector detector
- Radiological dispersion device
- Rally for Democracy and Development
- Random digit dialing
- Redding Municipal Airport
- Regression discontinuity design
- Renault Driver Development
- Responsibility-driven design
- Riddlesdown railway station
- Rosai–Dorfman disease
- Rubber duck debugging