| Stellenbosch University LaunchLab | Western Cape |
| Stellenbosh University | |
| Stem Connect | |
| Stempath Laboratories | |
| Stenden South Africa | |
| Stitch | |
| StokFella (Pty) Ltd | |
| Storm Business Solutions | Gauteng |
| StormBiz | Gauteng |
| Stormtech | Western Cape |
| Stouf Communications | Gauteng |
| Strang IT Consulting | Gauteng |
| Stratahost | |
| Strategic Online Marketing Services (Pty) Ltd | Gauteng |
| StrategyOnline | Western Cape |
| Stratosat Datacom SA (Pty) Ltd | |
| Streamnet Internet Solutions | KwaZulu-Natal |
| Strider | Gauteng |
| Studio 112 | |
| Studio 29 | Western Cape |
| Studio256 | Gauteng |
| Sulaco New Media (Pty) Ltd | Gauteng |
| Summit Networks | Gauteng |
| Sun Technosystems | |
| Suneldo | Northern Cape |
| SupertimePlus (Pty) Ltd | |
| Supima Technologies | Gauteng |
| SurfStats | Gauteng |
| Surpac | North West |
| Sw7 | Gauteng |
| SWART | |
| Swift Geospatial | |
| SwiftCom | Gauteng |
| SwiftCom (Pty) Ltd | Western Cape |
| Switch Telecom | Gauteng |
| SybaWeb | Western Cape |
| SyberGrupe | |
| Sybu Data | Western Cape |
| Symbionix | |
| Symbioses Technology Solutions | Gauteng |
| Symbiote Web Development | |
| Symphony Systems | Western Cape |
| Synapsis Software | |
| Synaq | Gauteng |
| Synch.cc | Western Cape |
| Synchramed (Pty) Ltd | Gauteng |
| Syncrony Digital | Gauteng |
| SynnCom CC | Gauteng |
| Synthesis | |
| Syrinx Communications | Gauteng |