| ST. Edward's Court Management Company Limited | Households | 1994 |
| ST. Edward's School Trading Limited | Real estate | 2024 |
| ST. Gilgen Ltd | Real estate | 2017 |
| ST. James's Property Group Limited | Extraterritorial | 2017 |
| ST. Luke's Oxford | Health & social care | 1986 |
| ST. Paul's Farms Limited | Real estate | 1973 |
| ST. Priestley Ltd | Transport & logistics | 2021 |
| St.Edward's School | Education | 1911 |
| Staalbaek Ltd | Information & communication | 2022 |
| Stable Strength Ltd | Arts & recreation | 2024 |
| Stacker Clothing Ltd | Wholesale & retail | 2021 |
| Stadium Capital Management (UK) Ltd. | Financial services | 2020 |
| Stadium Capital Management Europe LLP | | 2020 |
| Staltech Europe Limited | Information & communication | 2016 |
| Stamford Residential Limited | Construction | 2004 |
| Stancetime Property Management Limited | Households | 1998 |
| Standard Building Ltd | Construction | 2013 |
| Standard Oxford 03 Limited | Hospitality | 2003 |
| Standlake Star Ltd | Wholesale & retail | 2009 |
| Stanford in Oxford Foundation | Education | 1993 |
| Stanfosys Ltd | Information & communication | 2025 |
| Stanjo Ltd | Health & social care | 2015 |
| Stanlake Ltd | Households | 2020 |
| Stanley's Sweets and Treats Ltd | Wholesale & retail | 2021 |
| Stanlycrown Travels and Tours Limited | Administrative & support | 2023 |
| Stann Properties Ltd | Real estate | 2025 |
| Stannet Global Ltd | Information & communication | 2026 |
| Stanway Road Limited | Households | 2026 |
| Staple Hall Residents Association Limited | Real estate | 2013 |
| Staple Services Limited | Construction | 2022 |
| Star Cars Oxford Limited | Wholesale & retail | 2023 |
| Star Guest House Ltd | Hospitality | 2026 |
| Star Services Oxford Limited | Real estate | 2013 |
| Starjump Management Services Limited | Real estate | 2016 |
| Starlift Aviations Ltd | Transport & logistics | 2021 |
| Starlift Properties Ltd | Real estate | 2022 |
| Starlight Tuition Ltd | Education | 2024 |
| Starlight Tutors Ltd | Education | 2023 |
| Starness Limited | Real estate | 2018 |
| Starris Property Ltd | Real estate | 2022 |
| Start Fresh Cleaning Ltd | Administrative & support | 2024 |
| State of Ambition Ltd | Other services | 2012 |
| Stateful Robotics Ltd | Information & communication | 2025 |
| Statim Developments Ltd | Construction | 2021 |
| Station Road (Wheatley) Management Company Limited | Households | 1983 |
| Station View (Chesham) Owners Limited | Households | 2019 |
| Staveacre Flats Limited | Households | 1970 |
| Staveley Property Services Ltd | Real estate | 2023 |
| Staygo Solutions Ltd | Real estate | 2025 |
| Staywell Accommodation Ltd | Real estate | 2026 |
| STB Brickwork Limited | Construction | 2006 |
| Steady Heart Medical Limited | Health & social care | 2022 |
| Stealth Tactical UK Limited | Wholesale & retail | 2019 |
| Steeles PCS Ltd | Construction | 2016 |
| Steerwise Driving School Ltd | Education | 2025 |
| Stefan Cleaning Pro Ltd | Administrative & support | 2022 |
| Stefanie Clark Designs Ltd | Arts & recreation | 2021 |
| Stellar Clinic Limited | Health & social care | 2023 |
| Stemblue Ltd | Professional & scientific | 2019 |
| Stemm Global Scientific Society | Information & communication | 2021 |
| Stephen Boyce Surgical Services Limited | Health & social care | 2017 |
| Stephen Court Residents Association Limited | Households | 1984 |
| Stephen Donaldson Limited | Financial services | 2012 |
| Stephen G Davies Limited | Education | 2014 |
| Stephen Lanighan Ltd | Construction | 2018 |
| Stephen Lister Consulting Limited | Professional & scientific | 2005 |
| Stephen Spencer + Associates Ltd | Professional & scientific | 2023 |
| Sterling Lettings and Management Ltd | Other services | 2018 |
| Sterling Property Enterprises Limited | Real estate | 2018 |
| Sterling Recruitment (International) Ltd | Administrative & support | 2025 |
| Sternberg Limited | Administrative & support | 2013 |
| Stevco Limited | Real estate | 1938 |
| Steve Crewe Ltd | Transport & logistics | 2014 |
| Stevengale Limited | Real estate | 1982 |
| Steviant Design Company Ltd | Information & communication | 2014 |
| Stevrex Limited | Professional & scientific | 2025 |
| Stevrey Limited | Professional & scientific | 2025 |
| Stevrez Limited | Professional & scientific | 2025 |
| Stichting Oxfam International | | 1996 |
| Sticker Book Chats Company Limited | Wholesale & retail | 2026 |
| Stitch Alterations Ltd | Other services | 2015 |
| Stobart Haulage Limited | Transport & logistics | 2013 |
| Stockopedia Ltd | Information & communication | 2007 |
| Stoja Ltd | Hospitality | 2020 |
| Stoke Place Properties Limited | Real estate | 2013 |
| Stolivia Ltd | Wholesale & retail | 2020 |
| Stone and Clay Ltd | Construction | 2024 |
| Stone Bailey Ltd | Administrative & support | 2012 |
| Stone Barrell Ltd | Information & communication | 2021 |
| Stone House Home Limited(The) | Health & social care | 1986 |
| Stone Rouge Consulting Ltd. | Information & communication | 2014 |
| Stone's Electrical Services Limited | Administrative & support | 2014 |
| Stop & Shop Oxford Ltd | Wholesale & retail | 2024 |
| Stop Trafficking Worldwide CIC | Education | 2023 |
| Stored Solar Limited | Professional & scientific | 2007 |
| Storm Shift Ltd | Information & communication | 2025 |
| Stotek Ltd | Manufacturing | 2021 |
| Stovetek Ltd | Construction | 2013 |
| Stow Electrical Services Limited | Construction | 2016 |
| Stowood Capital Limited | Construction | 2023 |