| Search Signals | |
| Searchflow | |
| SearchSoftware | |
| Seceurtronics | North Holland |
| SECOMP Nederland GmbH | South Holland |
| SecuData | North Brabant |
| SecuPlus B.V. | Zeeland |
| Secura | North Holland |
| Secure Internet Machines (SIM) B.V. | North Holland |
| Secure Internet Services | South Holland |
| SecureConsult | |
| Secureness B.V. | North Holland |
| Security Academy | |
| Security Delta | |
| SecurityHive | |
| Secusystems | |
| SeedPact | |
| Seenons | |
| Self-screen B.V. | |
| Selles Automatisering B.V. | Overijssel |
| Semantica | South Holland |
| SemLab | South Holland |
| Semmie | |
| Sempro | |
| Sencio B.V. | |
| SendCloud | North Brabant |
| Sendcloud | |
| Seneca | South Holland |
| Senet | South Holland |
| Senhive B.V. | |
| Seniorweb Groningen | Groningen |
| Sensara | |
| Sense Health B.V. | |
| Sense-IT | Drenthe |
| Sensity | |
| Sensius | South Holland |
| Sensor Partners Nederland | North Brabant |
| Sensorfact | |
| Sensorfact | |
| Sensoterra B.V. | |
| Sentia | North Holland |
| Sentient Information Systems | North Holland |
| Senwa B.V. | South Holland |
| SEO Advies MKB | |
| SEO Effect | North Holland |
| SEO vrienden | |
| Seogi | |
| SEOguru | North Holland |
| SeraNovo B.V. | |
| Serendipity | |