| THM Refrigeration & Shop Fitting Ltd | Manufacturing | 2020 |
| Thoko Shining Star Limited | Health & social care | 2015 |
| Tholu Limited | Wholesale & retail | 2025 |
| Thomas & Gabriel Hillsborough Ltd | Real estate | 2023 |
| Thomas & Gabriel Solicitors Limited | Professional & scientific | 2017 |
| Thomas Collier Carpentry & Joinery Limited | Manufacturing | 2016 |
| Thomas Connelly Logistics Limited | Transport & logistics | 2018 |
| Thomas Daley Homes Limited | Construction | 2019 |
| Thomas Edwards Training Ltd | Education | 2022 |
| Thomas Eggar Trust Corporation Limited | Administrative & support | 1988 |
| Thomas ETS Limited | Transport & logistics | 2007 |
| Thomas Flinn & Co Limited | Manufacturing | 2014 |
| Thomas GC Mitchell Ltd | Health & social care | 2010 |
| Thomas Gray Development Ltd | Information & communication | 2016 |
| Thomas Rowley Limited | Arts & recreation | 2013 |
| Thomas Smith (Roofing Centres) Limited | Extraterritorial | 1995 |
| Thomas Turton Limited | Manufacturing | 1999 |
| Thomaschurch Ltd | Hospitality | 2021 |
| Thomason Physiotherapy Limited | Health & social care | 2022 |
| Thompson & Thomas LLP | | 2012 |
| Thompson & Wild Ltd | Real estate | 2026 |
| Thompson Associates (Sheffield) Limited | Professional & scientific | 1991 |
| Thompson Build and Developments Ltd | Construction | 2016 |
| Thompson Engineering Ltd | Manufacturing | 2014 |
| Thompsons Carpets Ltd | Wholesale & retail | 1999 |
| Thonet Limited | Manufacturing | 2000 |
| Thorcer Inc Ltd | Real estate | 2021 |
| Thorex Energy Ltd | Manufacturing | 2025 |
| Thorman & Co Ltd | Health & social care | 2014 |
| Thornbridge Estates Limited | Real estate | 2008 |
| Thorncliffe Community Sports | Arts & recreation | 2014 |
| Thorncliffe Community Sports Bar Ltd | Hospitality | 2015 |
| Thorncliffe Properties Limited | Real estate | 2019 |
| Thornewell Labs Ltd | Other services | 2025 |
| Thornhill Investments Ltd | Financial services | 2019 |
| Thornhill Properties Limited | Real estate | 2012 |
| Thornseat Lodge Limited | Hospitality | 2018 |
| Thornseat Weddings Limited | Other services | 2016 |
| Thornsett Court Management Limited | Households | 1984 |
| Thornton Blyth Ltd | Wholesale & retail | 2026 |
| Thorp Farms Ltd | Agriculture & fishing | 2011 |
| Thorpe Development Solutions Ltd | Construction | 2014 |
| Thorpe Solutions Construction Ltd | Construction | 2014 |
| Thorpe Solutions Properties Ltd | Real estate | 2020 |
| Thorplas Consultancy Ltd | Professional & scientific | 2023 |
| Thos. C. Wild Limited | Manufacturing | 2005 |
| Those Cherished Moments Limited | Administrative & support | 2024 |
| Thou Art Modified Ltd | Other services | 2018 |
| Thoutreddy Ltd | Wholesale & retail | 2024 |
| THQ Auto Traders Limited | Wholesale & retail | 2024 |
| THQ Real Estate Ltd | Real estate | 2023 |
| THQ Traders Ltd | Wholesale & retail | 2019 |
| THR Trading Ltd | Wholesale & retail | 2025 |
| Thread Architects Limited | Professional & scientific | 2013 |
| Threads of Hope Collective CIC | Health & social care | 2025 |
| Three Barrels Hospitality Ltd | Hospitality | 2026 |
| Three Brothers Group (Trading) Ltd | Financial services | 2026 |
| Three Brothers Group Ltd | Financial services | 2008 |
| Three Brothers Holdings Ltd | Real estate | 2017 |
| Three Five Two (Retford) Ltd | Wholesale & retail | 2025 |
| Three Galleys Ltd | Information & communication | 2019 |
| Three Pillars Projects Ltd Ltd | Construction | 2026 |
| Three PS Services Ltd | Health & social care | 2026 |
| Three Sister Zaytoon Limited | Wholesale & retail | 2021 |
| Three Wishes Ltd | Information & communication | 2024 |
| Threedee Music Ltd | Information & communication | 2021 |
| Threeeightytwo Limited | Administrative & support | 2010 |
| Threeonethree Estates Ltd | Administrative & support | 2016 |
| Threepoint Investments Ltd | Hospitality | 2024 |
| Threepwood Holdings Ltd | Real estate | 2024 |
| Threeroofscafe Limited | Hospitality | 2024 |
| THRI5 Project Consulting Ltd | Information & communication | 2018 |
| Thrillermill CNC Precision Machining Limited | Manufacturing | 1997 |
| Thrive Branding Limited | Professional & scientific | 2023 |
| Thrive Health & Wellness Business Coaching Ltd | Professional & scientific | 2020 |
| Thrive Physiotherapy Ltd | Other services | 2023 |
| Thrive Social Capital CIC | Professional & scientific | 2025 |
| Thrive South Yorkshire Ltd | Education | 2020 |
| Thrive-Ology Ltd | Health & social care | 2022 |
| Throgmorton Financial Advice Limited | Financial services | 2010 |
| Throne Solutions Limited | Information & communication | 2024 |
| Throttle Haus Ltd | Information & communication | 2025 |
| Through the Hoops Limited | Professional & scientific | 2002 |
| Thunder Security Ltd | Administrative & support | 2024 |
| Thunderlightning Recordings Limited | Information & communication | 2013 |
| Thuong Tran Property Ltd | Real estate | 2025 |
| Thurgoland Childcare | Administrative & support | 2002 |
| Thurgoland Holdings Company Limited | Financial services | 2023 |
| Thurgoland OUT of School Club Limited | Health & social care | 2003 |
| Thurgoland Private Hire Ltd | Transport & logistics | 2025 |
| Thurgoland Travel Ltd | Transport & logistics | 2014 |
| Thurlstone Property Ltd | Real estate | 2018 |
| Thurnham Services Ltd | Wholesale & retail | 2019 |
| Thyme Cafe Limited | Hospitality | 2003 |
| TI YAN PAI Ltd | Administrative & support | 2023 |
| Tiago Limited | Manufacturing | 2008 |
| Tiantianrong Trading Limited | Wholesale & retail | 2025 |
| Tianxinht Limited | Wholesale & retail | 2025 |
| TIB & GAB Limited | Transport & logistics | 2019 |
| Tibb & Co. Official Ltd | Wholesale & retail | 2025 |