| StartupBox z.s. | |
| StartupJobs | Prague |
| StartupJobs.com, s.r.o. | |
| StartUpStart | Prague |
| StartupYard | Prague |
| StickyPassword | South Moravian |
| Stofcom, s.r.o. | South Moravian |
| Stop Krádežím, spol. s r.o. | |
| Storm Type Foundry, s.r.o. | Prague |
| Storyous | |
| Strategic Consulting, s.r.o. | |
| Stratosyst, s.r.o. | |
| Stream Circle, a.s. | |
| Středisko společných činností AV ČR, v. v. i. | |
| Stren Tech, s.r.o. | |
| Studio 3P | |
| Studio 6.15 | |
| Studio dmm | South Bohemian |
| Studio DUHA, spol. s r.o. | |
| Studio Gabreta, spol. s r.o. | |
| Subreg | Prague |
| Suitcase Type Foundry | Prague |
| Suitest | |
| SUMA, spol. s r.o. | Prague |
| SUMO, s.r.o. | |
| Sunnysoft | Prague |
| Superdesk | |
| Superface | |
| SuperNakup.com | Prague |
| Support System | Hradec Králové |
| Survio | |
| SVCS Process Innovation, s.r.o. | |
| SVĚT-HUB | |
| SvetHostingu.cz | Moravian-Silesian |
| Svěžíweb.cz | Zlín |
| SychrovNET | |
| Syntea software group, a.s. | Prague |
| System Boost, a.s. | |
| System servis, s.r.o. | |
| System4u | |
| SystemOnLine.cz | Prague |
| t-alacarte.com | |
| T-Mobile Czech Republic, a.s. | Prague |
| T-SOFT, a.s. | Prague |
| TA Triumph-Adler Česká republika, s.r.o. | Prague |
| Talentor Advanced Search | Prague |
| TaNET West, s.r.o. | Plzeň |
| TAOX, s.r.o. | Zlín |
| TappyTaps, s.r.o. | |
| Taran, s.r.o. | Olomouc |