| Shaun Boylan Limited | Administrative & support | 2021 |
| Shears Court Limited | Real estate | 2014 |
| Shefford Bloodstock Services Limited | Arts & recreation | 1994 |
| Sherpa Real Estate Management Ltd | Extraterritorial | 2018 |
| SHM Electrical Limited | Construction | 2010 |
| Shriram Enterprises Ltd | Hospitality | 2023 |
| Siaad Ltd | Health & social care | 2022 |
| Siemea Limited | Professional & scientific | 2005 |
| Siendo Wellbeing Ltd | Health & social care | 2015 |
| Signpost Educational Limited | Wholesale & retail | 2007 |
| Silver Forge Farriers Ltd | Other services | 2012 |
| Simon Florey & SON Marquee Hire Limited | Administrative & support | 2008 |
| Simon Scott Limited | Professional & scientific | 2001 |
| Simply Motor Group Ltd | Wholesale & retail | 2024 |
| Single Gandt Holdings Limited | Professional & scientific | 2022 |
| Singtor Ventures Ltd | Wholesale & retail | 2025 |
| SIX Newbury Street Management Company Limited | Households | 2023 |
| Sixfive Design Ltd | Other services | 2022 |
| Skaiaco Ltd | Wholesale & retail | 2022 |
| SKC Occupational Health Consultancy Ltd | Health & social care | 2016 |
| Skyblue Scaffolding Solutions Limited | Construction | 2017 |
| Skybound Aerospace Limited | Professional & scientific | 2021 |
| SL Marine Trading Ltd | Wholesale & retail | 2023 |
| Slack Water Investments Limited | Real estate | 2020 |
| SMB Accountancy (Oxford) Ltd | Information & communication | 2019 |
| Snob & Lock Limited | Wholesale & retail | 2013 |
| Snowberry Stores Ltd | Hospitality | 2026 |
| Soar Cafe Ltd | Hospitality | 2025 |
| Socket & C Electrical Ltd | Construction | 2024 |
| Soft Ventures Limited | Information & communication | 2017 |
| Sole Avenue Ltd | Wholesale & retail | 2024 |
| Solution Cleaning Ltd | Administrative & support | 2014 |
| Sonder Nights Limited | Arts & recreation | 2023 |
| Sophie Sings Recording Co Ltd | Hospitality | 2025 |
| SOURCE23 Limited | Professional & scientific | 2011 |
| Spark Mason Ltd | Professional & scientific | 1996 |
| Specialist Letting Ltd | Real estate | 2017 |
| Spiller Construction Limited | Construction | 2024 |
| Spire Medical (Oxon) Limited | Manufacturing | 2014 |
| Spookyshop Ltd | Wholesale & retail | 2025 |
| Sporting Shots Ltd | Agriculture & fishing | 2018 |
| Sports Evolution Group Ltd | Real estate | 2022 |
| Sports Martial Arts Fitness Organisation Ltd | Arts & recreation | 2018 |
| Sportswize Ltd. | Wholesale & retail | 2003 |
| Springback Chronicle Limited | Households | 2021 |
| Springback Holdings Limited | Real estate | 2020 |
| Springfield Court (Wantage) Limited | Households | 2016 |
| Squareguard Ltd | Information & communication | 2024 |
| ST Giles Mews Management Company Limited | Households | 2002 |
| ST Swithin's Holdings Limited | Real estate | 1964 |
| ST. Michaels Residents Company Limited | Households | 1981 |
| Star Projections Limited | Health & social care | 2015 |
| Star Property & Management Group Limited | Construction | 2024 |
| Starveacre Limited | Agriculture & fishing | 2013 |
| Stephen Johns Design Ltd | Professional & scientific | 2022 |
| Stepping Stone Performing Arts Limited | Arts & recreation | 2019 |
| Sterling House (Bagpuize) Ltd | Households | 2021 |
| Stibbs & Sons Limited | Construction | 1960 |
| Stortrack Limited | Other services | 2025 |
| Stowhill Estates Limited | Real estate | 2016 |
| Straight Forward Communications Limited | Other services | 2006 |
| STRAIGHT6DESIGN Limited | Professional & scientific | 2018 |
| Stratara Risk Ltd | Administrative & support | 2026 |
| Stream Edge Management Limited | Real estate | 2005 |
| STUDIO37 Ltd | Manufacturing | 2026 |
| Subitis Medical Technologies Limited | Extraterritorial | 2021 |
| Success in Therapy Limited | Health & social care | 2018 |
| Sumif Online Consulting Limited | Information & communication | 2018 |
| Summer Guide Limited | Education | 2017 |
| Summit Performance Labs Ltd | Health & social care | 2026 |
| Superglow Creative LLP | | 2021 |
| Sushi Monsters Ltd | Wholesale & retail | 2019 |
| SW Engineering (Oxford) Limited | Professional & scientific | 2015 |
| SWA Arboriculture Ltd | Agriculture & fishing | 2024 |
| Swanbrook Properties Limited | Real estate | 2020 |
| Swash (Oxon) Ltd | Professional & scientific | 2015 |
| Sweep With ME Limited | Administrative & support | 2019 |
| Sydalls Limited | Professional & scientific | 2010 |
| Syndicut Communications Ltd | Professional & scientific | 2002 |
| Synnova Ltd | Financial services | 2025 |
| T & L Construction (Oxford) Limited | Construction | 2003 |
| T and M Guest House Limited | Hospitality | 2013 |
| T Baller UK Limited | Education | 2025 |
| T&M (Oxfordshire) Ltd | Hospitality | 2019 |
| Tadpole Cottage Limited | Information & communication | 2010 |
| Tank Security Contracts Limited | Administrative & support | 2019 |
| Taurus Fire Safety Limited | Professional & scientific | 2006 |
| Taylor & Sons Bakery Ltd | Manufacturing | 2025 |
| Taylor C M Limited | Wholesale & retail | 2022 |
| Taylor Robinson Resorts Ltd | Real estate | 2015 |
| Taylors DRY Cleaning Limited | Other services | 2011 |
| TBS Oxford Limited | Wholesale & retail | 2011 |
| TC Logistik Ltd | Transport & logistics | 2022 |
| TCC Oxfordshire Limited | Administrative & support | 2025 |
| Technical & Management Services (Overseas) Limited | Professional & scientific | 2002 |
| Techno Trade Global Ltd | Wholesale & retail | 2020 |
| TED Studio Limited | Professional & scientific | 2017 |
| Teenissi Care Services Ltd | Health & social care | 2023 |
| Teenissi Limited | Health & social care | 2023 |
| Tema Solutions Limited | Wholesale & retail | 2021 |