| THE Roebuck Country Inn Limited | Hospitality | 2021 |
| THE Saucy Farmer Ltd | Manufacturing | 2025 |
| THE Sauna Spa Ltd | Arts & recreation | 2025 |
| THE Seed Consulting Limited | Professional & scientific | 2016 |
| THE Shawfield Trust Limited | Education | 2004 |
| THE SIP Lewes Ltd | Hospitality | 2025 |
| THE Soap People Ltd | Manufacturing | 2018 |
| THE Sound Garden Retreat LLP | | 2024 |
| THE Sussex Archaeological Society | Arts & recreation | 1925 |
| THE Sussex Peasant Limited | Wholesale & retail | 2016 |
| THE Sustainable Footprint Consultancy Ltd | Professional & scientific | 2020 |
| THE Sweet Plant Company Ltd | Wholesale & retail | 2020 |
| THE TOX LAB Media Ltd | Information & communication | 2025 |
| THE Treasure Co Brighton Ltd | Wholesale & retail | 2025 |
| THE Very Fiery Dragons Limited | Manufacturing | 2024 |
| THE Volly (Lewes) Ltd | Hospitality | 2026 |
| THE White House (Bexhill) Management Company Limited | Administrative & support | 2003 |
| THE WIG Department Ltd | Arts & recreation | 2007 |
| THE Workstation (London) Limited | Wholesale & retail | 2001 |
| The-Stitchery (Lewes) Limited | Wholesale & retail | 2008 |
| The-Stitchery Shop Limited | Wholesale & retail | 2026 |
| Theia Insights, Inc. | | 2023 |
| Theplot Ltd | Administrative & support | 2025 |
| Thesherpa Ltd | Education | 2024 |
| Think Strategy Ltd | Professional & scientific | 2017 |
| Thomas David Decorating Ltd | Construction | 2024 |
| Thomas Paine: Legacy CIC | Education | 2024 |
| Thompson Property Lettings Ltd | Real estate | 2026 |
| Thoughtful Consulting Ltd | Professional & scientific | 2025 |
| Three Sixty Sport Limited | Arts & recreation | 2014 |
| Thriverare Limited | Professional & scientific | 1987 |
| TI (Eastbourne) Limited | Hospitality | 2011 |
| Tigermoth Coffee Roasters Ltd | Wholesale & retail | 2023 |
| TIL Tomorrow Theatre Company CIC | Arts & recreation | 2021 |
| Tile Kiln Management Company Limited | Households | 2003 |
| Tillingbourne Syndicate Ltd | Agriculture & fishing | 2026 |
| Tilton Technologies Limited | Manufacturing | 2018 |
| Timberyard Lane (12-18) Management Company Limited | Extraterritorial | 2014 |
| Timberyard Lane (Lewes) Management Company Limited | Households | 2013 |
| Tine Craft Training Limited | Education | 2025 |
| Titanium Beech Opco Limited | Real estate | 2018 |
| Tizz's Lewes Ltd | Real estate | 2024 |
| TL Education Consultancy Ltd | Education | 2022 |
| TLC Floorings Limited | Construction | 2009 |
| TM Studio Productions Ltd | Information & communication | 2004 |
| TOM Grant Guiding Ltd | Arts & recreation | 2019 |
| Tompsett QS Services Limited | Professional & scientific | 2020 |
| Toms Engineering Ltd | Professional & scientific | 2019 |
| Tony Hilton Golf Ltd | Wholesale & retail | 2025 |
| Tooth Fairy Sussex Limited | Health & social care | 2003 |
| Top HAT Stage and Screen School Sussex Ltd | Arts & recreation | 2019 |
| Torchlight Holdings Limited | Financial services | 2020 |
| Torner CNC Limited | Wholesale & retail | 2011 |
| Touch Typing Hub Ltd | Education | 2022 |
| Tournesol Consulting Ltd | Administrative & support | 2011 |
| Townley-Jones Ltd | Information & communication | 2019 |
| TPF Estates Limited | Real estate | 2022 |
| TPH Holdings Limited | Financial services | 2018 |
| Tradepack Software Limited | Information & communication | 2026 |
| Tradestar Glazing Systems Limited | Construction | 2015 |
| Transgender Trend Ltd | Education | 2019 |
| Transparent Healthcare Ltd | Information & communication | 2018 |
| Treatment Choice Ltd | Information & communication | 2014 |
| Trend Analysis Limited | Financial services | 1987 |
| Triagonal Software Limited | Information & communication | 2005 |
| Trinity Learning Ltd | Education | 2018 |
| Trio Works Ltd | Real estate | 2023 |
| Triway Ltd | Wholesale & retail | 2006 |
| Trouble and Strife Theatre Ltd | Education | 2019 |
| Truth and Goodness Limited | Arts & recreation | 2022 |
| TRUTH2POWER Ltd | Professional & scientific | 2011 |
| Tuffset Limited | Wholesale & retail | 2023 |
| Tuppence Clothing Ltd | Wholesale & retail | 2025 |
| Turkuaz Lewes Limited | Real estate | 2021 |
| Turner Communications Limited | Information & communication | 2021 |
| Turning Point Global With Femi Emmanuel Ltd | Other services | 2023 |
| Turnpike (Horam) Ltd | Construction | 2020 |
| Turrell Developments Ltd | Real estate | 2016 |
| Turrell Group Limited | Real estate | 2025 |
| TWA Consulting Ltd | Professional & scientific | 2022 |
| Two Islands Ventures Limited | Professional & scientific | 2022 |
| Uckfield Community Fridge CIC | Hospitality | 2020 |
| Uckfield Logistics Training Services Limited | Professional & scientific | 2023 |
| UK Commons Ltd | Real estate | 2024 |
| Ukstudyonline Ltd | Professional & scientific | 2021 |
| Understory Limited | Professional & scientific | 2025 |
| Undistractable Ltd | Professional & scientific | 2022 |
| Unearthed Build Ltd | Construction | 2023 |
| Uniko Limited | Other services | 2015 |
| Unique 17 Limited | Administrative & support | 2026 |
| Unitas Home Care Limited | Health & social care | 2012 |
| Unity Lewes CIC | Arts & recreation | 2018 |
| Unlikely Books Ltd | Arts & recreation | 2015 |
| Unlock Your Golf Ltd | Extraterritorial | 2021 |
| Upper College Farm Ltd | Agriculture & fishing | 2022 |
| Upside London Limited | Professional & scientific | 2012 |
| Utter Limited | Information & communication | 2012 |
| V.F.K. Groundwork Contractors Ltd. | Construction | 2002 |
| V2 Food UK Limited | Manufacturing | 2022 |
| Valiciti Limited | Information & communication | 2025 |