| Samba.ai | |
| Samo Brno | |
| Samo Systems, spol. s r.o. | |
| Santiago Lab | |
| Saperta, s.r.o. | |
| SAPRO, s.r.o. | Moravian-Silesian |
| SATCOM | Prague |
| SATinternet.info, s.r.o. | |
| SatisMeter | |
| Scaleo | |
| SCS Software s.r.o. | Prague |
| SCS Software, s.r.o. | |
| SCT Cell Manufacturing, s.r.o. | |
| SDMK Design Czech, s.r.o. | |
| SE-MO Data | Moravian-Silesian |
| SEA, spol. s r.o. | Prague |
| SEAL Communication, s.r.o. | |
| SearchTeam | |
| SeCons Ltd | Prague |
| SEKO system, s.r.o. | Moravian-Silesian |
| Sendmark.io | Prague |
| SENO, spol. s r.o. | Prague |
| Sense Arena | |
| Sentien HQ, s.r.o. | |
| SEO Expert, a.s. | Prague |
| Septim | |
| Server Mechanics, s.r.o. | |
| Servodata, a.s. | Ústí nad Labem |
| Sewio Networks, s.r.o. | |
| seznamzbozi.cz | Prague |
| SH.cz, s.r.o. | Prague |
| Sharry | |
| Shean s.r.o. | South Moravian |
| Shopsys, s.r.o. | Moravian-Silesian |
| Shoptet, s.r.o. | Prague |
| Showmax Engineering | |
| SICONET, a.s. | |
| Siesta Labs | |
| Siesta Solution, s.r.o. | |
| Sigma Soft, spol. s .r.o. | |
| Signals Network | |
| Signi | |
| SigutLabs | |
| Simac Technik ČR, a.s. | Prague |
| Simona Biosystems, s.r.o. | |
| Simpleway Europe, a.s. | |
| Simplity | |
| SiteOne, s.r.o. | |
| Skinners Technologies, s.r.o. | |
| SKLINET, s.r.o. | |