MRR
- Birmingham Middle ring road
- José María Velasco Ibarra Airport
- Kuala Lumpur Middle Ring Road 1
- Kuala Lumpur Middle Ring Road 2
- Libor
- Machine Robo Rescue
- Mackay Ring Road
- Manchester Road Race
- Manila Railroad Company
- Marcel Reich-Ranicki
- Marine Raider Regiment
- Master Resell Right
- Maximumrocknroll
- Mean reciprocal rank
- Middle Ring Road (Tianjin)
- Modulating retro-reflector
- Multi Rolle Radio
- My Restaurant Rules
- Philippine National Railways
- Thomas Robert Shannon Broughton