| Toweringly Limited | Manufacturing | 2025 |
| Towermead (Peterborough) Management Company Limited | Households | 2009 |
| Town Farm MAN. Co. Limited | Households | 2018 |
| Townbase Holdings Limited | Information & communication | 2017 |
| Townbase Limited | Information & communication | 2017 |
| Townbase Media Group Limited | Information & communication | 2023 |
| Townley Memorial Hall | Arts & recreation | 2003 |
| Townsend Residents Association Limited | Households | 1986 |
| Townsends (Cambridge) Limited | Extraterritorial | 1998 |
| Toxbio Consulting Ltd | Professional & scientific | 2025 |
| Toynbee Gray Holdings Ltd | Financial services | 2021 |
| Toynbee Investments Limited | Construction | 2017 |
| Toynbee Property Capital Limited | Real estate | 2017 |
| Toyo Sangyo Shokai Limited | | 1989 |
| TPA Cambridge Ltd | Professional & scientific | 2021 |
| TPG Services Limited | Information & communication | 1993 |
| Tpmsmart Limited | Wholesale & retail | 2019 |
| TPO12 Ltd | Professional & scientific | 2025 |
| TQ Scientific Limited | Professional & scientific | 2006 |
| TR 2014 Limited | Real estate | 2013 |
| TR Global Group Limited | Financial services | 2018 |
| TR Site Services Ltd | Construction | 2026 |
| Track Apps Ltd | Professional & scientific | 2016 |
| Track Field & Life Ltd | Arts & recreation | 2024 |
| Tracking Academy Ltd | Education | 2024 |
| Tracy Newman & Co Limited | Professional & scientific | 2001 |
| Tracytools Machine Co., Ltd | Extraterritorial | 2015 |
| Tradavex Ltd | Administrative & support | 2023 |
| Trade Cambridge Limited | Wholesale & retail | 2020 |
| Trade Holdings Limited | Real estate | 2015 |
| Trade Recruitment (East Anglia) Ltd | Administrative & support | 2008 |
| Trade Recruitment Limited | Administrative & support | 2008 |
| Tradebeta Investment LP | | 2015 |
| Tradeline Giveaways Ltd | Arts & recreation | 2025 |
| Trading Time Ltd | Financial services | 2009 |
| Traditional Roofwork Contractors Ltd | Construction | 1997 |
| Tradivo Ltd | Wholesale & retail | 2025 |
| Tradizioni Limited | Wholesale & retail | 2018 |
| Trafalgar Accounting and Taxation Services LLP | | 2002 |
| Traffic International | Professional & scientific | 1999 |
| Tragheim Electrical Ltd | Construction | 2018 |
| Train 2 Track Ltd | Education | 2026 |
| Trajecture Ltd | Professional & scientific | 2014 |
| Tramonto Vino Limited | Wholesale & retail | 2020 |
| Trams Investment Co Limited | Extraterritorial | 2026 |
| Tramuntana Consultants Ltd | Education | 2024 |
| Traniss Group Ltd | Wholesale & retail | 2026 |
| Tranquillo Saunas Limited | Other services | 2026 |
| Trans Almea Ltd | Transport & logistics | 2019 |
| Trans+ History Week CIC | Health & social care | 2024 |
| Transaction Management Services UK Limited | Professional & scientific | 2017 |
| Transceve Ltd | Information & communication | 2025 |
| Transcriptogen Ltd | Professional & scientific | 2013 |
| Transfers 4U - Cambridge Executive Airport Taxi Transfers Ltd | Transport & logistics | 2023 |
| Transform Future Ltd | Information & communication | 2022 |
| Transformation AI Ltd | Information & communication | 2026 |
| Transformational Data Insights(Tdi) Ltd | Information & communication | 2022 |
| Transforming Stress Limited | Professional & scientific | 2017 |
| Transglobal Energy Solutions Limited | Wholesale & retail | 2012 |
| Transit Cable Products Limited | Wholesale & retail | 2017 |
| Transition BIO Limited | Professional & scientific | 2020 |
| Translationbox Limited | Professional & scientific | 2003 |
| Transolta Ltd | Professional & scientific | 2011 |
| Transpire BIO UK Ltd | Wholesale & retail | 2023 |
| Transport Intelligence Limited | Professional & scientific | 2002 |
| Transthera Ltd | Professional & scientific | 2012 |
| Transtrans Ltd | Professional & scientific | 2013 |
| Trapped Animal Records Limited | Information & communication | 2019 |
| Travel & Achieve Limited | Education | 2017 |
| Travel Hunter Ltd | Hospitality | 2023 |
| Travel Internations Ltd | Administrative & support | 2017 |
| Travel Link Taxi Services Limited | Transport & logistics | 2022 |
| Travel Trade Group International Limited | Other services | 2012 |
| Travel Trade Group Limited | Administrative & support | 2017 |
| Travel Union Finance Limited | Information & communication | 2018 |
| Travellers Toolkits Limited | Information & communication | 2004 |
| Travelstash Ltd | Wholesale & retail | 2023 |
| Trax Electrical Ltd | Construction | 2026 |
| Trdata Technology Limited | Information & communication | 2019 |
| Treasure Data (UK) Limited | Information & communication | 2020 |
| Treasures and Times Ltd. | Administrative & support | 2015 |
| Treasures Import and Export Co., Ltd | Wholesale & retail | 2025 |
| Treatly Ltd | Information & communication | 2026 |
| Treble Group UK Limited | Professional & scientific | 2021 |
| Trebol Limited | Administrative & support | 2013 |
| Treefusion Ltd. | Agriculture & fishing | 2022 |
| Tregoing Consulting Ltd. | Information & communication | 2012 |
| Treharne Surgical Limited | Health & social care | 2023 |
| Trend Kombin Clothing Ltd | Wholesale & retail | 2025 |
| Trendchem Group Co., Ltd | Extraterritorial | 2012 |
| Trentway Limited | Real estate | 2025 |
| Treo Consulting Limited | Professional & scientific | 2019 |
| Treo Endurance Ltd | Education | 2025 |
| Treswithian Ltd | Financial services | 2021 |
| Treve Cambridge Ltd | Manufacturing | 2025 |
| Treven Holdings Ltd | Wholesale & retail | 2026 |
| Trevi Properties Limited | Real estate | 2024 |
| Trevor Newling Removals Limited | Transport & logistics | 2012 |
| Trevor Page Marquees Limited | Administrative & support | 2007 |
| Trey Consulting Ltd | Professional & scientific | 2018 |