| S | Saint; Scotland (of creation in peerage of); South |
| (S) | (in Navy) Paymaster; Scotland |
| S/Ldr | Squadron Leader |
| s | succeeded |
| SA | South Africa; South Australia; Societe Anonyme |
| SAAF | South African Air Force |
| sac | qualified at small arms technical long course |
| SACEUR | Supreme Allied Commander Europe |
| SACRO | Scottish Association for the Care and Resettlement of Offenders |
| SACSEA | Supreme Allied Command, SE Asia |
| SAE | Society of Automobile Engineers (US) |
| SAInstMM | South African Institute of Mining and Metallurgy |
| Salop | Shropshire |
| Sarum | Salisbury |
| SAS | Special Air Service |
| Sask | Saskatchewan |
| SASO | Senior Air Staff Officer |
| SBStJ | Serving Brother, Most Venerable Order of the Hospital of St John of Jerusalem |
| SC | Star of Courage (Canada); Senior Counsel; South Carolina |
| SCA | Society of Catholic Apostolate (Pallottine Fathers); Societe en Commandite par Actions |
| ScD | Doctor of Science |
| SCF | Senior Chaplain to the Forces; Save the Children Fund |
| Sch | School |
| SCI | Society of Chemical Industry |
| SCL | Student in Civil Law |
| SCM | State Certified Midwife; Student Christian Movement |
| Scot | Scotland; Scottish |
| ScotBIC | Scottish Business in the Community |
| SCOTVEC | Scottish Vocational Education Council |
| SD | Staff Duties; South Dakota |
| SDA | Social Democratic Alliance; Scottish Diploma in Agriculture; Scottish Development Agency |
| SDLP | Social Democratic and Labour Party |
| SDP | Social Democratic Party |
| SE | South East |
| SEAC | South-East Asia Command |
| SEATO | South-East Asia Treaty Organization |
| SEC | Security Exchange Commission |
| SEN | State Enrolled Nurse |
| SERC | Science and Engineering Research Council |
| Serv(s) | Service(s} |
| SFA | Securities and Futures Authority |
| Sgt | Sergeant |
| SHAEF | Supreme Headquarters, Allied Expeditionary Force |
| SHAPE | Supreme Headquarters, Allied Powers, Europe |
| SHEFC | Scottish Higher Education Funding Council |
| SHHD | Scottish Home and Health Department |
| SIB | Shipbuilding Industry Board; Securities and Investments Board |
| SIESO | Society of Industrial and Emergency Services Officers |
| SIS | Secret Intelligence Service |
| SJ | Society of Jesus (Jesuits) |
| SKGB | Ski Club of Great Britain |
| SL | Serjeant-at-Law; Sociedad Lirnitada |
| SLD | Social and Liberal Democrats |
| SLG | Community of Sisters of the Love of God |
| slr | solicitor |
| SM | Medal of Service (Canada}; Master of Science; Officer qualified for Submarine Duties |
| SMMT | Society of Motor Manufacturers and Traders Ltd |
| SMO | Senior Medical Officer; Sovereign Military Order |
| SMP | Senior Managers' Program |
| SNH | Scottish Natural Heritage |
| SNP | Scottish National Party |
| SNR | Society for Nautical Research |
| SO | Staff Officer; Scientific Officer; Symphony Orchestra |
| SOAS | School of Oriental and African Studies |
| Soc | Society |
| SOE | Special Operations Executive |
| SOGAT | Society of Graphical and Allied Trades |
| Som | Somerset |
| Sov | Sovereign |
| sp | sine prole (without issue) |
| SPAB | Society for the Protection of Ancient Buildings |
| SPCA | Society for the Prevention of Cruelty to Animals |
| SPCK | Society for Promoting Christian Knowledge |
| SPG | Society for the Propagation of the Gospel |
| SPTL | Society of Public Teachers of Law |
| Sq | Square |
| SQA | Sitara-i-Quaid-i-Azam (Pakistan) |
| Sqdn | Squadron |
| SR | Special Reserve; Southern Railway; Southern Region (BR) |
| SRC | Science Research Council; Students' Representative Council |
| SRN | State Registered Nurse |
| SRO | Supplementary Reserve of Officers; Self-Regulatory Organisation |
| SRP | State Registered Physiotherapist |
| SS | Saints; Straits Settlements; Steamship |
| SSC | Solicitor before Supreme Court (Scotland); Sculptors Society of Canada; Societas Sanctae Crucis (Society of the Holy Cross); Short Service Commission |
| SSEB | South of Scotland Electricity Board |
| SSJE | Society of St John the Evangelist |
| SSO | Senior Supply Officer; Senior Scientific Officer |
| SSRC | Social Science Research Council |
| SSStJ | Serving Sister, Most Venerable Order of the Hospital of St John of Jerusalem |
| St | Street; Saint |
| Staffs | Staffordshire |
| STB | Sacrae Theologiae Baccalaureus (Bachelor of Sacred Theology) |
| STC | Senior Training Corps |
| STD | Sacrae Theologiae Doctor (Doctor of Sacred Theology) |
| STh | Scholar in Theology |
| Stip | Stipend; Stipendiary |
| STM | Sacrae Theologiae Magister (Master of Sacred Theology) |
| STV | Scottish Television |
| SUNY | State University of New York |
| Supp Res | Supplementary Reserve (of Officers) |
| Supt | Superintendent |
| Surgn | Surgeon |
| surv | surviving |
| SW | South-west |
| SWPA | South West Pacific Area |