| Swan Court (Eynsham) Limited | Real estate | 2004 |
| Swan Fire (U.K.) Ltd | Administrative & support | 2015 |
| Sweet Alyssum Advisory Limited | Professional & scientific | 2025 |
| Sweet Developments Limited | Construction | 2023 |
| Sweet Lettings Limited | Real estate | 2023 |
| SWI Ltd | Professional & scientific | 2026 |
| Swift Dog Training Limited | Other services | 2021 |
| Swift Upvc UK Ltd | Extraterritorial | 2010 |
| Swiftwave International Ltd | Information & communication | 2023 |
| Swim Oxford Ltd | Other services | 2025 |
| Swirral Wind Intelligence Limited | Information & communication | 2026 |
| Syaf Group Ltd | Financial services | 2026 |
| Syaf Limited | Real estate | 2023 |
| Sydney & Blake Ltd | Professional & scientific | 2023 |
| Sygma Venture Group Ltd | Extraterritorial | 2016 |
| Symba Consulting Ltd | Professional & scientific | 2025 |
| Synolos CIC | Manufacturing | 2011 |
| SYP Venues Ltd | Hospitality | 2023 |
| Syplex IT Limited | Information & communication | 2024 |
| Sysc Ltd | Real estate | 2023 |
| Systems in Ltd | Information & communication | 2026 |
| T & J Gardiner Limited | Administrative & support | 2002 |
| T D GAS Services Ltd | Construction | 2024 |
| T S Trotman Limited | Professional & scientific | 2015 |
| T-Hem Coaching Ltd | Arts & recreation | 2021 |
| T.Butler Consulting Ltd | Professional & scientific | 2021 |
| T.D.R. Valuations Limited | Administrative & support | 2003 |
| T3F Ltd | Real estate | 2022 |
| T5EC Ltd | Professional & scientific | 2026 |
| Tailored Ventures Limited | Real estate | 1999 |
| Tails and Trails Oxfordshire Ltd | Other services | 2024 |
| Tails at Peace Ltd | Professional & scientific | 2025 |
| Taimar Cars Oxford Ltd | Transport & logistics | 2024 |
| Taiwo.B Ltd | Wholesale & retail | 2021 |
| Talent Suite Limited | Information & communication | 2019 |
| Talisman International Limited | Professional & scientific | 2021 |
| Tall Projects Ltd | Information & communication | 2014 |
| Tam's Investment Limited | Real estate | 2022 |
| Tamanna Homes Ltd | Real estate | 2025 |
| Tamayos Travels Ltd | Administrative & support | 2020 |
| Tamegon Consulting Ltd. | Professional & scientific | 2009 |
| Tamoray Limited | Construction | 1988 |
| Tamu Bristol Limited | Hospitality | 2021 |
| Tank Pros Ltd | Real estate | 2020 |
| Taste Addict Limited | Hospitality | 2020 |
| TAU Homes Ltd | Construction | 2012 |
| TAW Fitzwilliam Ltd | Professional & scientific | 2019 |
| Taylors Brewery Management Co. Limited | Households | 1999 |
| Taylors Funeral Care Ltd | Other services | 2025 |
| Taylors' Cotswold Construction Ltd | Construction | 2018 |
| Tayworth Holdings Limited | Real estate | 2019 |
| TBS Web Services Limited | Information & communication | 2022 |
| Team Landscape Ltd | Extraterritorial | 2007 |
| Teamdave Ltd | Other services | 2026 |
| Teardrop Bar Limited | Hospitality | 2018 |
| Tech Collective Group Limited | Professional & scientific | 2023 |
| Technispec Limited | Professional & scientific | 2019 |
| Techtonic Marine Limited | Professional & scientific | 2024 |
| Tecton Projects Limited | Professional & scientific | 1988 |
| Teepee Vips Ltd | Administrative & support | 2025 |
| Teetimesonly Ltd. | Administrative & support | 2024 |
| Temple Court Bloxham Management Limited | Households | 2010 |
| Temporary Site Technologies Limited | Information & communication | 2022 |
| TEN Elephants Limited | Professional & scientific | 2002 |
| TEN TEN Agency Ltd | Administrative & support | 2023 |
| Tenens EDE Homes Limited | Construction | 2016 |
| Tenens EDE Limited | Construction | 1998 |
| Tenpin Bowling Stroud Ltd | Education | 2019 |
| Tensegrity Media Limited | Arts & recreation | 2020 |
| Terma Kitchens Limited | Construction | 2001 |
| Tern Aviation Limited | Professional & scientific | 2006 |
| Terra Botanical Plants Limited | Agriculture & fishing | 2024 |
| Tetatetr Ltd | Real estate | 2020 |
| Tev&Co Ltd | Hospitality | 2023 |
| TEX Automotive Limited | Manufacturing | 1986 |
| Tezel Electrics Limited | Construction | 2010 |
| TG Maintenance and Special Projects Ltd | Construction | 2019 |
| TG Projects Ltd | Administrative & support | 2016 |
| TG Property and Development Ltd. | Construction | 2020 |
| TG Racing Limited | Arts & recreation | 2019 |
| Thame Planning Consultancy Limited | Professional & scientific | 2002 |
| Thames Court Management Company Limited | Households | 1986 |
| Thames Crane Services Limited | Wholesale & retail | 2002 |
| Thames Street Barbers Ltd | Other services | 2025 |
| Thames Valley Facilities Management Ltd | Construction | 2017 |
| Thames Valley Heating and Plumbing Ltd | Construction | 2020 |
| THE 13TH Theatre Company Limited | Arts & recreation | 2008 |
| THE Abbey Recording Company Limited | Information & communication | 2016 |
| THE Advanced Sales Network Limited | Professional & scientific | 2016 |
| THE Angry PIG Ltd | Information & communication | 2004 |
| THE Artistic Leaded Glass Company Limited | Construction | 2006 |
| THE Association of Mctimoney-Corley Skeletal Therapists Limited | Other services | 2001 |
| THE B-Hive Academy Ltd | Education | 2025 |
| THE Banbury Cake Company Limited | Manufacturing | 2003 |
| THE Barns at Orchardleigh Ltd | Financial services | 2024 |
| THE Bell (Standlake) Management Company Limited | Households | 2024 |
| THE Bell Faringdon Ltd | Hospitality | 2019 |
| THE Besom in Witney | Other services | 2011 |
| THE Bigger Life Limited | Real estate | 2019 |
| THE Bishops Farm Mill Management Company Ltd | Households | 2013 |