| Sussex Medical Centre Ltd | Health & social care | 2006 |
| Sussex Model Centre (1981) Limited | Wholesale & retail | 1973 |
| Sussex PAD Hotel | | 1996 |
| Sussex Sailability | Arts & recreation | 2001 |
| Swanacre Limited | | 1984 |
| Swiftech Precision Engineering Limited | Manufacturing | 2007 |
| Swimco Pools (South) Limited | Transport & logistics | 1992 |
| Switched on Southern Limited | Wholesale & retail | 2007 |
| Sylvarna Kitchen Design Limited | Wholesale & retail | 1983 |
| Syzygy Consultants Ltd | Education | 2014 |
| T & N Builders Ltd | Construction | 2006 |
| TA Housing Ltd | Real estate | 2020 |
| Tagfirst Retail Solutions Ltd. | Manufacturing | 1991 |
| Tamarisk Properties Limited | Real estate | 2007 |
| TAP Mind the MAP Limited | Administrative & support | 2001 |
| Tapruna Limited | Real estate | 1998 |
| Tavistock Insurance Services Limited | Financial services | 1987 |
| Taylor Contractors Limited | Construction | 2008 |
| Technology Matters Limited | Information & communication | 1992 |
| TEJ Delivery Ltd | Transport & logistics | 2024 |
| Templespa Limited | Extraterritorial | 2000 |
| Tessam Developments Limited | Real estate | 1984 |
| Thakeham Newick LLP | | 2022 |
| Thakeham West Horsley LLP | | 2021 |
| That Security Software Ltd | Professional & scientific | 2025 |
| THE A-Z Tax Return Company Limited | Professional & scientific | 2001 |
| THE Accounting and Tax Centre Ltd | Professional & scientific | 2007 |
| THE Autarky Machine Co. Limited | Professional & scientific | 2007 |
| THE BED and Mattress Centre Ltd | Wholesale & retail | 2005 |
| THE BSW Foundation | Other services | 2012 |
| THE Card Aisle Ltd | Wholesale & retail | 2003 |
| THE Chichester Ship Canal Trust | Transport & logistics | 2002 |
| THE Close Partnership Limited | Professional & scientific | 2002 |
| THE Cowdray Heritage Trust | Arts & recreation | 1997 |
| THE Egremont Charitable Trust | Health & social care | 2001 |
| THE Engagement Academy Limited | Administrative & support | 2016 |
| THE European Association of Quality, Safety and Environmental Auditors Ukeig | | 1995 |
| THE Finishing Components Company Limited | Wholesale & retail | 1997 |
| THE Fitting Company Limited | Wholesale & retail | 2003 |
| THE Full SP Limited | Professional & scientific | 2002 |
| THE Garden Show Limited | Arts & recreation | 2003 |
| THE Green House Sussex Holdings Ltd | Agriculture & fishing | 1977 |
| THE Hampshire Connection Limited | Administrative & support | 1997 |
| THE Informed Parent Company Limited | Information & communication | 1999 |
| THE Lancing College Chapel Trust | Arts & recreation | 2005 |
| THE Letting People Ltd | Real estate | 2002 |
| THE Lorraine O'Brien Partnership Ltd | Professional & scientific | 2009 |
| THE Mill House Group Limited | Financial services | 1997 |
| THE Morning Advertiser Limited | Information & communication | 1989 |
| THE Neville & Jones Partnership | | 1998 |
| THE New Montessori Pre-School | Education | 2000 |
| THE Nursery Family Ltd | Education | 2002 |
| THE On-Line Partnership Limited | Financial services | 2000 |
| THE People's Pension Trustee Limited | Financial services | 2012 |
| THE Petworth Cottage Trust | Arts & recreation | 1995 |
| THE Residents of 61 Queens Road Limited | Households | 2005 |
| THE RHU Limited | Other services | 2006 |
| THE Shopno Foundation | Health & social care | 2020 |
| THE Stanmore House Residents Company Limited | Households | 2006 |
| THE Wisdom Track Ltd | Other services | 2021 |
| Therapy Hutt Ltd | Other services | 2019 |
| Theresa Vigilance Care Limited | Health & social care | 2015 |
| Third Sense Limited | Professional & scientific | 2003 |
| Thornton Meadow Maintenance Co. Ltd. | Households | 1993 |
| Tikutiku Ltd | Hospitality | 2023 |
| Timothy ROE Fine Jewellery Limited | Wholesale & retail | 1995 |
| TL Financial Consultancy Limited | Financial services | 2003 |
| TMH Property Maintenance Limited | Construction | 2007 |
| Toddington Nurseries Holdings Limited | Financial services | 2023 |
| Toggs Hall (Builders) Limited | Construction | 1996 |
| TOM Smee Limited | Construction | 2006 |
| Tonic Management Limited | Arts & recreation | 2000 |
| Tony Roberts TV Limited | Other services | 2004 |
| Topturf Irrigation (Service) Ltd | Construction | 2004 |
| Tracey Samuel Design Limited | Wholesale & retail | 2001 |
| Tractruc Bi-Modal Limited | Extraterritorial | 1999 |
| Tralaway International Limited | Transport & logistics | 1974 |
| Transport Command Limited | Manufacturing | 1983 |
| Travel Matters Limited | Administrative & support | 1999 |
| Travel Places (WS) Limited | Information & communication | 1985 |
| Tree Huggers of Worthing Limited | Professional & scientific | 2004 |
| Treetop Investment Limited | Real estate | 2008 |
| Trend Marketing Services Ltd | Information & communication | 2021 |
| Trenear Close Management Company Limited | Households | 2000 |
| Trescom Transport Limited | Transport & logistics | 2002 |
| Trimec Industries (Europe) Limited | Professional & scientific | 2000 |
| Trimmain Limited | Wholesale & retail | 2007 |
| Tritax Prime Distribution Carry Limited Partnership | | 2013 |
| Trotyn Croft Management (Bognor) Limited | Households | 1987 |
| Troutleap Property Management Limited | Real estate | 2004 |
| Truck Train Developments Limited | Transport & logistics | 1996 |
| Truevision Limited | Wholesale & retail | 1979 |
| Tt&Gizmo Limited | Information & communication | 2024 |
| Tulip Rose Limited | Professional & scientific | 2006 |
| Turners Plumbing Limited | Construction | 2007 |
| Twinair Aviation Limited | Manufacturing | 1997 |
| Twist Creative Limited | Professional & scientific | 2005 |
| UK Cook Shop Ltd | Wholesale & retail | 2005 |
| Ultimate Pilates Limited | Arts & recreation | 2002 |
| Unispares Limited | Wholesale & retail | 2000 |