| Tribe Digital | |
| Tribeca Technology Ltd | Scottish Borders |
| Tribosonics | |
| Trichromic, LLP | Greater London |
| Trickle Data Insights Ltd | |
| Tricostar Software Ltd | |
| Trident BioPharm Solutions | |
| Trifle Solution | |
| Trig Avionics Ltd | |
| TRIG Creative Ltd | |
| Trigger.dev | |
| Trilan IT | |
| Trilby Multimedia Ltd | West Midlands |
| Trillenium (UK) Ltd | |
| Trillium Flow Technologies | |
| Trilogy Communications Ltd | Cambridgeshire |
| Trilogy Group | Gloucestershire |
| Trinity Heriot | Edinburgh |
| Trinity Integrated Systems Ltd | |
| Trinityweb Ltd | |
| TRINT | Greater London |
| Trint Ltd | |
| Trio Medicines Ltd | |
| Triodos Bank UK Ltd | Bristol |
| triOpsis Ltd | Buckinghamshire |
| Trip Solutions | |
| Triple Software Ltd | |
| TripStax | |
| Trisoft Ltd | Nottinghamshire |
| Trison UK | Hertfordshire |
| Tristan Capital Partners | Greater London |
| Tristar Web Solutions | Hertfordshire |
| Tritec | Hampshire |
| Tritech International Ltd | |
| Tritech International Ltd | |
| Triton consulting | Norfolk |
| Triumph Technologies Ltd | Oxfordshire |
| TRM International Ltd | Merseyside |
| Trolley Payments UK Ltd | |
| Tromero Ltd | |
| TRON Media Ltd | |
| Tron Systems Ltd | West Lothian |
| Tronisoft Ltd | Berkshire |
| Tropic Biosciences UK Ltd | |
| Tru.ID | |
| True Capital Ltd | |
| True Digital Ltd | |
| True Track Software Ltd | |
| Truebyte Ltd | East Sussex |
| TrueLayer | Greater London |