| Tagz | Greater Manchester |
| Tahninial | South Yorkshire |
| Tailify | |
| Tailor Bio | |
| Tailor Made Technologies | |
| Tailormade Creative Design Ltd | |
| Tailr | |
| Take A Byte Ltd | Essex |
| Take Note | |
| Take Note Publishing Ltd | Surrey |
| Talenetic Ltd | |
| Talent Network | |
| Talespinners Studios Ltd | |
| Talis Capital Ltd | Greater London |
| Talisman Therapeutics Ltd | |
| TALK Electronics Ltd | Surrey |
| Talking Technology Ltd | Greater London |
| TalkLife Ltd | |
| Talkmobile Ltd | Berkshire |
| TalkTalk | |
| tallhatDesign | Somerset |
| Talli Systems | |
| Talos Automation | |
| Tam Design Group | Bedfordshire |
| Tam Digital | Buckinghamshire |
| Tamar IT Ltd | Cambridgeshire |
| Tamar Telecommunications | Devon |
| Tameside Computer Repair | |
| TAMI | |
| Tandem Bank Ltd | Lancashire |
| Tandem Creative | Hertfordshire |
| Tangcreative | Cambridgeshire |
| Tangy Media | Gloucestershire |
| Tank | |
| Tanzarine Technology Ltd | Essex |
| Tao Analytics | |
| Tap App Ltd | |
| Tap2Tag Ltd | |
| TAPE Consultancy Ltd | |
| Tappit Media Ltd | |
| Taramsys Ltd | |
| Taran Microsystems Ltd | Hampshire |
| Taran3D | |
| Tarci | |
| Target Components Ltd | West Yorkshire |
| Target Internet | |
| Targeted SEO | |
| Targeting Innovation Ltd | |
| Targetjobs | Oxfordshire |
| Tarragon Solutions Ltd | Hertfordshire |