| Sgraffit | Hainaut |
| Shaping Europe’s digital future | |
| Shayp S.A. | |
| Shown | |
| Showpad | East Flanders |
| Shyfter S.A. | |
| Sigasi nv | East Flanders |
| SigmaConso | Brussels-Capital |
| Sign2Pay.com N.V. | |
| Silex Insight | Walloon Brabant |
| Silverfin | East Flanders |
| Simac | Flemish Brabant |
| Simera Sense | |
| SimpleBackups | |
| Sipro Media B.V. | Flemish Brabant |
| Sirris | Antwerp |
| SITA | |
| Site2host | West Flanders |
| SiteDev | East Flanders |
| Siteffect | Flemish Brabant |
| SiteHosting | East Flanders |
| SiteManager | |
| Sitemark | |
| Skipr S.A. | |
| Skwarel S.A. | |
| Skyline Communications | West Flanders |
| Skyscrapers | |
| SLYTIO | Hainaut |
| Smallsites Webdesign | East Flanders |
| Smart Design S.P.R.L. | Walloon Brabant |
| Smartbeam | Brussels-Capital |
| Smartcheckups CommV | |
| SmartConnect N.V. | |
| Smartfin | |
| Smartmat N.V. | |
| SmartProjects | Limburg |
| Smartworx | |
| Smovin | |
| Sms ExtraPro | Liège |
| Snijders Compuservice B.V.B.A. | Limburg |
| Snikpic S.R.L. | |
| SOA People | Walloon Brabant |
| Société européenne pour la formation des ingénieurs | |
| Soda Data N.V. | |
| Sodeco N.V. | West Flanders |
| Soft Naert | West Flanders |
| Soft&Log | Liège |
| Softconstruct N.V. | |
| Softo2 | Antwerp |
| Softron Microcomputing S.A. | |