| R of O | Reserve of Officers |
| R&D | Research and Development |
| (R) | Reserve |
| RA | Royal (Regiment of) Artillery; Royal Academician |
| RAA | Regional Arts Association; Royal Australian Artillery |
| RAAF | Royal Auxillary Air Force; Royal Australian Air Force |
| RAAMC | Royal Australian Army Medical Corps |
| RAC | Royal Armoured Corps; Royal Automobile Club; Royal Agricultural College |
| RACGP | Royal-Australian College of General Practitioners |
| RACP | Royal Australasian College of Physicians |
| RADA | Royal Academy of Dramatic Art |
| RAE | Royal Australian Engineers; Royal Aerospace Establishment (formerly Royal Aircraft Establishment) |
| RAEC | Royal Army Educational Corps |
| RAeS | Royal Aeronautical Society |
| RAF | Royal Air Force |
| RAFA | Royal Air Force Association |
| RAFO | Reserve of Air Force Officers |
| RAFVR | Royal Air Force Volunteer Reserve |
| RAI | Royal Anthropological Institute of Great Britain and Ireland; Radio-Audizioni Italiane |
| RAIC | Royal Architectural Institute of Canada |
| RAM | (Member of) Royal Academy of Music |
| RAMC | Royal Army Medical Corps |
| RAN | Royal Australian Navy |
| RANR | Royal Australian Naval Reserve |
| RANVR | Royal Australian Naval Volunteer Reserve |
| RAOC | Royal Army Ordnance Corps |
| RAPC | Royal Army Pay Corps |
| RARO | Regular Army Reserve of Officers |
| RAS | Royal Astronomical Society; Royal Asiatic Society; Recruitment and Assessment Services |
| RASC | Royal Army Service Corps |
| RASE | Royal Agricultural Society of England |
| RAuxAF | Royal Auxiliary Air Force |
| RAVC | Royal Army Veterinary Corps |
| RB | Rifle Brigade |
| RBA | Member, Royal Society of British Artists |
| RBL | Royal British Legion |
| RBS | Royal Society of British Sculptors |
| RC | Roman Catholic |
| RCA | Royal College of Art; Royal Company of Archers; Member, Royal Canadian Academy of Arts; (Member of) Royal Cambrian Academy |
| RCAF | Royal Canadian Air Force |
| RCAS | Royal Central Asian Society |
| RCDS | Royal College of Defence Studies |
| RCEME | Royal Canadian Electrical and Mechanical Engineers |
| RCHA | Royal Canadian Horse Artillery |
| RCHM | Royal Commission on Historical Monuments |
| RCM | (Member of) Royal College of Music |
| RCN | Royal Canadian Navy; Royal College of Nursing |
| RCNR | Royal Canadian Naval Reserve |
| RCNVR | Royal Canadian Naval Volunteer Reserve |
| RCOG | Royal College of Obstetricians and Gynaecologists |
| RCP | Royal College of Physicians, London |
| RCPath | Royal College of Pathologists |
| RCPSG | Royal College of Physicians and Surgeons of Glasgow |
| RCPsych | Royal College of Psychiatrists |
| RCS | Royal College of Surgeons of England; Royal Corps of Signals; Royal College of Science |
| RCSI | Royal College of Surgeons in Ireland |
| RCT | Royal Corps of Transport |
| RCVS | Royal College of Veterinary Science; Royal College of Veterinary Surgeons |
| RD | Rural Dean; Royal Naval and Royal Marine Forces Reserve Decoration |
| RDC | Rural District Council |
| RDI | Royal Designer for Industry (Royal Society of Arts) |
| RDS | Royal Dublin Society |
| RE | Royal Engineers; Fellow, Royal Society of Painter-Printmakers (formerly of Painter-Etchers and Engravers); Religious Education |
| REACH | Retired Executives Action Clearing House |
| recd | received |
| REconS | Royal Economic Society |
| Regnl | Regional |
| Regt | Regiment |
| rels | relations |
| REME | Royal Electrical and Mechanical Engineers |
| Renfrews | Renfrewshire |
| Rep/rep | Representative/representative |
| Res | Resident; Resigned; Reserve; Research |
| ret | retired |
| Rev | Reverend; Review |
| RFA | Royal Field Artillery; Royal Fleet Auxiliary |
| RFC | Royal Flying Corps; Rugby Football Club |
| RFD | Reserve Force Decoration |
| RFU | Rugby Football Union |
| RGA | Royal Garrison Artillery |
| RGI | Royal Glasgow Institute of the Fine Arts |
| RGJ | Royal Green jackets |
| RGN | Registered General Nurse |
| RGS | Royal Geographical Society |
| RHA | Royal Horse Artillery; Royal Hibernian Academy; Regional Health Authority |
| RHAS | Royal Highland and Agricultural Society of Scotland |
| RHBNC | Royal Holloway and Bedford New College, London |
| RHF | Royal Highland Fusiliers |
| RHG | Royal Horse Guards |
| RHQ | Regional Headquarters |
| RHR | Royal Highland Regiment |
| RHS | Royal Horticultural Society; Royal Humane Society |
| RI | Rhode Island; (Member of) Royal Institute of Painters in Water Colours |
| RIA | Royal Irish Academy |
| RIAMC | Royal Indian Army Medical Corps |
| RIAS | Royal Incorporation of Architects in Scotland |
| RIASC | Royal Indian Army Service Corps |
| RIBA | (Member of) Royal Institute of British Architects |
| RIBI | Rotary International in Great Britain and Ireland |
| RIC | Royal Irish Constabulary; Royal Institute of Chemistry |
| RICS | Royal Institution of Chartered Surveyors |
| RIF | Royal Inniskilling Fusiliers |
| RIIA | Royal Institute of International Affairs |
| RIM | Royal Indian Marines |
| RIN | Royal Indian Navy |
| RINA | Royal Institution of Naval Architects |
| RINVR | Royal Indian Naval Volunteer Reserve |
| RIPA | Royal Institute of Public Administration |
| RLC | Royal Logistic Corps |
| Rlrd(s) | Railroad(s) |
| RLSS | Royal Life Saving Society |
| Rlwy | Railway |
| RM | Royal Marines; Resident Magistrate; Registered Midwife |
| RMA | Royal Military Academy, Sandhurst; Royal Marine Artillery |
| RMB | Rural Mail Base |
| RMC | Royal Military College Sandhurst |
| RMCS | Royal Military College of Science |
| RMFVR | Royal Marine Forces Volunteer Reserve |
| RMLI | Royal Marine Light Infantry |
| RMN | Registered Mental Nurse |
| RMO | Resident Medical Officer(s) |
| RMP | Royal Military Police |
| RMS | Royal Microscopical Society; Royal Mail Steamer; Royal Society of Miniature Painters |
| RN | Royal Navy; Royal Naval; Registered Nurse |
| RNAS | Royal Naval Air Service |
| RNC | Royal Naval College |
| RND | Royal Naval Division |
| RNEC | Royal Naval Engineering College |
| RNIB | Royal National Institute for the Blind |
| RNID | Royal National Institute for Deaf People (formerly Royal National Institute for the Deaf) |
| RNLI | Royal National Lifeboat Institution |
| RNR | Royal Naval Reserve |
| RNSC | Royal Naval Staff College |
| RNVR | Royal Naval Volunteer Reserve |
| RNVSR | Royal Naval Volunteer Supplementary Reserve |
| RNXS | Royal Naval Auxiliary Service |
| RNZAC | Royal New Zealand Armoured Corps |
| RNZAF | Royal New Zealand Air Force |
| RNZN | Royal New Zealand Navy |
| RNZNVR | Royal New Zealand Naval Volunteer Reserve |
| ROC | Royal Observer Corps |
| ROF | Royal Ordnance Factories |
| ROI | Member, Royal Institute of Oil Painters |
| RoSPA | Royal Society for the Prevention of Accidents |
| Roy | Royal |
| RP | Member, Royal Society of Portrait Painters |
| RPC | Royal Pioneer Corps |
| RPMS | Royal Postgraduate Medical School |
| RRC | Royal Red Cross |
| RSA | Royal Scottish Academician; Royal Society of Arts; Republic of South Africa |
| RSAA | Royal Society for Asian Affairs |
| RSAS | Royal Surgical Aid Society |
| RSC | Re al Society of Canada; Royal Society of Chemistry; Royal Shakespeare Company |
| RSCN | Registered Sick Children's Nurse |
| RSE | Royal Society of Edinburgh |
| RSF | Royal Scots Fusiliers |
| RSGS | Royal Scottish Geographical Society |
| RSL | Royal Society of Literature; Returned Services League of Australia |
| RSM | Royal School of Mines |
| RSPB | Royal Society for Protection of Birds |
| RSPCA | Royal Society for Prevention of Cruelty to Animals |
| RSPP | Royal Society of Portrait Painters |
| RSSPCC | Royal Scottish Society for Prevention of Cruelty to Children |
| RSW | Member, Royal Scottish Society of Painters in Water Colours |
| Rt Hon | Right Honourable |
| Rt Rev | Right Reverend |
| Rt. | Right |
| RTC | Royal Transport Corps |
| RTE | Radio Telefis Eireann |
| RTO | Railway Transport Officer |
| RTPI | Royal Town Planning Institute |
| RTR | Royal Tank Regiment |
| RTS | Religious Tract Society; Royal Toxophilite Society; Royal Television Society |
| RU | Rugby Union |
| RUC | Royal Ulster Constabulary |
| RUI | Royal University of Ireland |
| RUKBA | Royal United Kingdom Beneficent Association |
| RUR | Royal Ulster Regiment |
| RURAL | Society for the Responsible Use of Resources in Agriculture and on the Land |
| RUSI | Royal United Services Institute for Defence Studies (formerly Royal United Service Institution) |
| RVC | Royal Veterinary College |
| RWAFF | Royal West African Frontier Force |
| RWF | Royal Welch Fusiliers |
| RWS | (Member of) Royal Society of Painters in Water Colours |
| RYA | Royal Yachting Association |
| RYS | Royal Yacht Squadron |