| SeoGoal | |
| SeoGuideline SEO | |
| Seoline GmbH | North Rhine-Westphalia |
| Seonative | |
| seoPOINT | Berlin |
| SEOprofiler | Rhineland-Palatinate |
| Seosmart GmbH | Berlin |
| seosupport GmbH | Berlin |
| Seotrust GmbH & Co. KG | Hesse |
| seo|maxx Michael Pauls | Berlin |
| SEPAexpress | |
| Sepia GmbH & Co. KG | North Rhine-Westphalia |
| sepp.med Software GmbH | Bavaria |
| Sequantrix GmbH | |
| Sequiserve GmbH i.L. | |
| Sercos International e.V. | Baden-Württemberg |
| Sereact GmbH | |
| Serenitystudio | North Rhine-Westphalia |
| Sergei Pleis Softwareentwicklung | Hesse |
| SerialInternet | Hamburg |
| Serious Business GmbH | Bavaria |
| Serious Games Solutions | |
| Serious Play | |
| SerNet Service Network GmbH | Lower Saxony |
| SeRo Systems GmbH | |
| Sertronics AG | Hamburg |
| Sertronics GmbH | Hamburg |
| Serum Life Science Europe GmbH | |
| ServeNet GmbH | |
| ServerMind | Bavaria |
| Serverreinigung | Berlin |
| service & media online-werbung GmbH | Schleswig-Holstein |
| Service für Sicherheitstechnik GmbH | Bavaria |
| Service Unlimited | Thuringia |
| service-system GmbH | |
| servicepro Agentur für Dialogmarketing und Verkaufsförderung GmbH | |
| Serviceware SE | |
| ServiceZeit.com | Saxony |
| SERVOWATT Leistungselektronik GmbH | Baden-Württemberg |
| SES RFID GmbH | |
| SET – Software Engineering GmbH | Bavaria |
| Setis GmbH | Hesse |
| Setting HQ GmbH | |
| sevDesk GmbH | Baden-Württemberg |
| Seven Principles AG | North Rhine-Westphalia |
| Seven Senders GmbH | |
| Seven.One Entertainment Group GmbH | |
| SevenCs GmbH | Hamburg |
| SEVENSTAX GmbH | Lower Saxony |
| seventech GmbH | |