R
- RAAF – Royal Australian Air Force (Australia)
- RAF – Royal Air Force (UK)
- RAN – Royal Australian Navy (Australia)
- RATO – Rocket Assisted Take Off
- RCSC – Royal Canadian Sea Cadets (Canada)
- REMF – Rear Echelon Mother Fucker
- RFL – Response Force Leader
- RMC – Royal Military College of Canada (Canada) in Kingston, Ontario
- RN – Royal Navy (UK)
- ROE – Rules Of Engagement
- ROMA Data, Right Out of My Ass Data. Unverifiable created data (different from SWAG)
- ROWPU – Reverse Osmosis Water Purification Unit
- RNZAF – Royal New Zealand Air Force (New Zealand)
- RPG – Rocket-Propelled Grenade
- RPM – Rounds per minute
- RS – RatShit (Australia – related to US – Unserviceable)
- RSS – Regional Security System (Caribbean)
- RTB – Return To Base
- RV – Rendez-Vous
Read more about this topic: List Of U.S. Government And Military Acronyms