| Stevenage Circuits Ltd | Hertfordshire |
| Stewart Investors | |
| Stewart Technology Ltd | Scottish Borders |
| STFC Business & Innovation | |
| Stickyeyes | West Yorkshire |
| Stiff Design | Warwickshire |
| Stilo | Wiltshire |
| Stilu Wen Solutions | Staffordshire |
| Stinky Ink.com Ltd | Shropshire |
| Stinkyink.com | |
| Stirling IT Ltd | Stirling |
| Stirling IT Web Design | |
| STL Communications Ltd | Oxfordshire |
| Stock Sourcing Wholesales Ltd | Essex |
| Stockall Electronics Ltd | |
| Stockport College | |
| Stockport Computers | Greater Manchester |
| Stocks Design | Leicestershire |
| Stok.ly | |
| Stoke Web Services | Staffordshire |
| Stone Group Ltd | Staffordshire |
| Stone Venture Partners Ltd | |
| Stoneridge | Dundee |
| Stop Go Networks Ltd | |
| Storacall Group | Surrey |
| Storacall Ltd | Gloucestershire |
| Store Valley | Suffolk |
| Storetec Services Ltd | |
| Storm Consultancy (EU) Ltd | Somerset |
| Storm Internet | Oxfordshire |
| Storm Technologies | Hertfordshire |
| STORM Therapeutics Ltd | |
| Storm Website Design | Aberdeen |
| Storm3 | |
| StormCloud Games Ltd | |
| Stormnet Media Ltd | Worcestershire |
| Stortech Electronics Ltd | Essex |
| StoryFutures | |
| StoryStream | Greater London |
| Stotles | |
| Stox | Gibraltar |
| Straal Ltd | |
| Strafe Ltd | Nottinghamshire |
| Straker Systems Ltd | |
| STRANDcreative.com | |
| Strange | Dorset |
| Stranmillis University College | |
| Strata Consulting Ltd | |
| Stratech | |
| Strategic Blue | |