| Strategic Maintenance Planning Ltd | Wiltshire |
| Strategic Resources European Recruitment Consultants | |
| Strategically Digital Marketing Ltd | |
| Strategies | Hampshire |
| StrategiQ Group Ltd | Greater London |
| Strategy 4 AI | |
| Strategy Plus (UK) Ltd | West Midlands |
| Stratford College London | |
| Strathspey Capital Ltd | |
| Stratos Creative Ltd | |
| Stratosvir Ltd | |
| Stratton & English Software Ltd | South Yorkshire |
| Stratum | |
| Strawberrysoup Ltd | West Sussex |
| Strawdog Studios | Derbyshire |
| Stream Studio Ltd | Leicestershire |
| Stream Web | Leicestershire |
| Streamba | Aberdeen |
| streamGo | |
| Streaming Video Provider | Greater London |
| Streaming Wizard Ltd | Warwickshire |
| StreamSoft Development Ltd | |
| Streetbank | |
| Streetbees | |
| Streetbees | |
| Streets Heaver | Lincolnshire |
| Strictly Sales & Marketing | |
| Stride Media | |
| Stride.VC, LLP | |
| Strident Computer Systems | Suffolk |
| Strikalite | Staffordshire |
| Strive Digital | |
| Strive Group | |
| Strolll | |
| Strongnet | Hampshire |
| StrongSoft Ltd | |
| Stroud Instruments Ltd | Gloucestershire |
| Structured Internet Ltd | Torfaen |
| Structured IT Solutions | Suffolk |
| Structured Software Systems Ltd | Cumbria |
| StructureFlow | |
| Stryve | |
| STS Digital Ltd | |
| STS PC | Greater Manchester |
| Stuart Tyrrell Developments | Greater Manchester |
| stuartkerrs.com | |
| StudentStore | Suffolk |
| Studio 14 | |
| Studio 24 | Cambridgeshire |
| Studio 74 Creative Design | Somerset |