| Three System Solutions (Rail) Ltd | Construction | 2025 |
| Threefifteen Limited | Professional & scientific | 2025 |
| THRI5 Ltd | Professional & scientific | 2025 |
| Thrive Clinic Ltd | Health & social care | 2025 |
| Thrive Executive Coaching Limited | Professional & scientific | 2026 |
| Thrive Together Community CIC | Education | 2025 |
| Thrive Together Consultancy Ltd | Education | 2024 |
| Thrivetogether Group Ltd | Professional & scientific | 2026 |
| TI GR Limited | Other services | 2024 |
| TIA UK 2020 Ltd | Health & social care | 2020 |
| Tibcor Limited | Construction | 2014 |
| Tidu Limited | Hospitality | 2020 |
| Tiga Hair Spa Ltd | Administrative & support | 2010 |
| Tiggyz Ltd | Other services | 2020 |
| Tikka Palace Limited | Hospitality | 2024 |
| Tiktok Supplies Ltd | Wholesale & retail | 2025 |
| Tilatili Ltd | Transport & logistics | 2023 |
| Tilbrook Design Ltd | Professional & scientific | 2024 |
| Tile Proud Ltd | Construction | 2019 |
| TIM Cooper 3D Limited | Professional & scientific | 2013 |
| TIM DON Racing Ltd | Arts & recreation | 2019 |
| TIM Foster Limited | Other services | 2008 |
| TIM Vice Group Limited | Other services | 2016 |
| Timber & Light Ltd | Construction | 2020 |
| Time Assured Limited | Manufacturing | 2011 |
| Time to Shine (Mansfield) Ltd | Administrative & support | 2021 |
| Tiny Haven Ltd | Information & communication | 2024 |
| Titan Developments Limited | Administrative & support | 2003 |
| Titan Stretchfilm Limited | Other services | 2010 |
| Titanium Fitness Nottingham Ltd | Arts & recreation | 2024 |
| Titanworks LAB Ltd | Manufacturing | 2025 |
| Titchfield Garage Ltd | Wholesale & retail | 2019 |
| Titchfield Park Dental Clinic Ltd | Health & social care | 2007 |
| Titchfield Property Limited | Real estate | 2017 |
| TJ Mansfield Ltd | Real estate | 2020 |
| TJ Motor Repairs Ltd | Wholesale & retail | 2025 |
| TJB (Mansfield) Ltd | Construction | 2025 |
| Tjmw Limited | Real estate | 2025 |
| TJR Flooring Ltd | Construction | 2026 |
| TJS Joinery Trustee Company Ltd | Professional & scientific | 2022 |
| TJW Garage Ltd | Administrative & support | 2016 |
| TK Smith Limited | Construction | 2012 |
| Tkba Martial Arts Ltd | Other services | 2022 |
| TKD Ventures Ltd | Wholesale & retail | 2021 |
| TKS Lets Ltd | Real estate | 2024 |
| TLC Group International Ltd | Construction | 2022 |
| TMG Nottingham Ltd | Wholesale & retail | 2020 |
| Tmpuk Ltd | Financial services | 2023 |
| TMR International Transport Limited | Transport & logistics | 2018 |
| TMU Gym Ltd | Arts & recreation | 2025 |
| TNK Stores Ltd | Wholesale & retail | 2025 |
| TNS Lotus Ltd | Wholesale & retail | 2025 |
| TNS Super Mart Ltd | Wholesale & retail | 2026 |
| TNT Service Centre Limited | Wholesale & retail | 2011 |
| TO the Moon and Back Foster Care Limited | Health & social care | 2017 |
| Today Care Ltd | Health & social care | 2020 |
| Toludan Ltd | Health & social care | 2026 |
| TOM Morgan Pictures (Manufacturing) Limited | Manufacturing | 2011 |
| TOM Stenson H&S Limited | Administrative & support | 2023 |
| Tomex Logistic Ltd | Transport & logistics | 2025 |
| Tomlinson Plumbing Limited | Construction | 2003 |
| Tomper Investments Limited | Real estate | 2004 |
| Toni Solutions Ltd | Construction | 2026 |
| Toothill Prestige Limited | Wholesale & retail | 2023 |
| Top Chemistry Tutor Ltd | Education | 2024 |
| Top Class Transporter Limited | Transport & logistics | 2025 |
| Top Sense Limited | Wholesale & retail | 2025 |
| Topgrade Sportswear Holdings Limited | Professional & scientific | 2007 |
| Topgrade Sportswear Limited | Wholesale & retail | 1995 |
| Toplogik Construction Limited | Construction | 2013 |
| Topmarks Property Developments Ltd | Construction | 2024 |
| Topmarks Property Investments Ltd | Real estate | 2026 |
| Topmarks Property Ltd | Households | 2022 |
| Topmost Management Limited | Administrative & support | 2026 |
| Tops 2 Heels Limited | Wholesale & retail | 2021 |
| Tops Mini Market Ltd | Wholesale & retail | 2025 |
| Tops Pizza & Chicken (Mansfield) Limited | Hospitality | 2025 |
| Tops Pizza Chicken Ltd | Hospitality | 2025 |
| Tops Pizza Mansfield Ltd | Hospitality | 2024 |
| Toray Textiles Europe Limited | Manufacturing | 1989 |
| Torque Tune Developments Limited | Manufacturing | 2011 |
| Total Healthcare Solutions Limited | Health & social care | 2015 |
| Total Image Inc Limited | Other services | 2014 |
| Total Integrated Solutions (Group) Limited | Manufacturing | 2019 |
| Total Integrated Solutions (Holdings) Limited | Manufacturing | 2016 |
| Total Integrated Solutions Limited | Manufacturing | 1951 |
| Total Toolmaking Solutions Ltd | Financial services | 2024 |
| Total Trim Solutions Limited | Wholesale & retail | 2011 |
| Total Victory Care Ltd | Health & social care | 2021 |
| Totalsite FM Ltd | Administrative & support | 2026 |
| Totsville Limited | Arts & recreation | 2024 |
| Touch of Charm Ltd | Wholesale & retail | 2022 |
| Touch UP Pens Ltd | Wholesale & retail | 2024 |
| Touchpoints Business Marketing Limited | Professional & scientific | 2021 |
| Tough Coat Solutions Ltd | Construction | 2023 |
| Toughened Glass Limited | Manufacturing | 2023 |
| Tour Construction Limited | Construction | 2010 |
| Tovikiel Culinary IP Strategyltd Ltd | Professional & scientific | 2026 |
| Tower (Derbyshire) Limited | Real estate | 2005 |
| Town Rentals Ltd | Real estate | 2024 |