| StarApps | |
| Start it Accelerate | |
| Start it Accelerate | |
| Startup Europe | Brussels-Capital |
| Startup Europe News | |
| Startup Europe Partnership | Brussels-Capital |
| Startup Factory | |
| Startup Scaleup | Brussels-Capital |
| Startup.Flanders | |
| Startups.be | Brussels-Capital |
| Stellar Data Recovery B.V. | Brussels-Capital |
| Stellar Development | |
| Step ITS | Walloon Brabant |
| StoryMe | |
| STRATENET S.P.R.L. | Namur |
| Stream Software | |
| StriveCloud | |
| Stuart | Antwerp |
| Students for Innovation & Cooperation | |
| Studio Emma | |
| Studio Webvision | |
| Studio2.0 | Namur |
| Studiopointcarré | Liège |
| Supplimax | |
| SupplyStack N.V. | |
| SurfPlus | Flemish Brabant |
| Sweepatic N.V. | |
| SweepBright N.V. | |
| Sybilla | East Flanders |
| Sygel | Antwerp |
| Sygma-D S.R.L. | Walloon Brabant |
| Sygmanet.be | Limburg |
| Sym3 | West Flanders |
| Synchrone | Liège |
| Syneton B.V. | |
| Synexis S.P.R.L. | Brussels-Capital |
| Syngulon S.A. | |
| Syscol S.P.R.L. | Brussels-Capital |
| Système D B.V.B.A. | East Flanders |
| T-Mining N.V. | |
| T-Productions | East Flanders |
| T-Regs | Flemish Brabant |
| Tactics | |
| TAKEOFFANTWERP | |
| Tangent Works | |
| Tappable | |
| Tapptic | Brussels-Capital |
| Tase Research S.A. | Brussels-Capital |
| Team Solutions | |
| team.blue | East Flanders |