| Total SEO Services | South Yorkshire |
| Total Systems plc | |
| Total Technology | Hertfordshire |
| Total Telephone Solutions | |
| Total Training Solutions (South-West) Ltd | Bristol |
| Total Web Development | Greater Manchester |
| Total Web Solutions | Greater Manchester |
| Totality Services | |
| Totalize Media | |
| Totally Appenin | |
| Totally Communications | Greater London |
| Totally Smart Homes Ltd | |
| TotallyMoney | |
| Totalscope IT Services Ltd | Lancashire |
| Totem Learning Ltd | |
| Toucan Computing Ltd | Greater London |
| Toucan Graphics | West Lothian |
| Toucan Internet, LLP | Essex |
| Touch Panel Products | Gloucestershire |
| Touch Screen Systems | Cambridgeshire |
| Touch-Base Ltd | Dorset |
| TouchFinder | |
| Touchlab Ltd | |
| Touchlight | |
| Touchlight | |
| TouchRight Software | |
| Touchstar ATC Ltd | East Sussex |
| TouchStone Capital Group Holdings Ltd | |
| Toughfruit Digital | Devon |
| Toward | |
| Tower Studios | |
| TownsWeb Archiving Ltd | Northamptonshire |
| Toxik Software | Cambridgeshire |
| Tozaro | |
| TPG | |
| TPP | West Yorkshire |
| TPXimpact Ltd | |
| TQC Ltd | Nottinghamshire |
| TR Computers | Cheshire |
| TR Control Solutions Ltd | Surrey |
| Trac Communications Ltd | North Yorkshire |
| Trace Services | Hertfordshire |
| Trace Web Design | Dorset |
| Tracebit | |
| Traced Ltd | |
| Trackdown Consultants | Herefordshire |
| Tracker Intelligence | Glasgow |
| Trackershop-UK | Greater London |
| Tracksys Ltd | |
| Tracsis plc | |