| Shinsung E&G Co., Ltd | Gyeonggi |
| Shinsung University | |
| Shock Utility | Seoul |
| Shutagen | Ulsan |
| SI Imaging Services | |
| SiG | Seoul |
| Siliconarts, Inc. | |
| Silla University | |
| SillaJen, Inc. | Seoul |
| Simmtech Co., Ltd | North Chungcheong |
| Singyeongju University | |
| siRNAgen Therapeutics | |
| SIXAI | Seoul |
| SK Biopharmaceuticals Co., Ltd | |
| SK Broadband Co., Ltd | Seoul |
| SK Chemicals | |
| SK Hynix, Inc. | Gyeonggi |
| SK Shieldus | Gyeonggi |
| SK Siltron Co., Ltd | North Gyeongsang |
| SK Telecom | Seoul |
| Skelter Labs Corporation | Seoul |
| SKONEC Entertainment Co., Ltd | Seoul |
| Sky Labs, Inc. | |
| SL Investment Co., Ltd | Seoul |
| SM Soft Lab Co., Ltd | Seoul |
| Smart Korea PCB | Seoul |
| Smart Light Technology, Inc. | Gyeonggi |
| Smart Motion Co., Ltd | |
| Smart Solutions Company | Gyeonggi |
| Smartdata Co., Ltd | Seoul |
| Smartro Co., Ltd | Seoul |
| SMG Electronics Co.,Ltd | Gyeonggi |
| Smile Serve Co., Ltd | Gyeonggi |
| Smilegate Investment | Seoul |
| SMT Corporation | Gyeonggi |
| SN BioScience | Gyeonggi |
| SNJ | Seoul |
| SNJ | |
| Snow Corporation | Gyeonggi |
| SNU Compbio Lab | |
| SNU Entrepreneurship Center | Seoul |
| SO & Company | |
| Socar | |
| SoftBank Ventures Asia | Seoul |
| SoftFlow Co., Ltd | Gyeonggi |
| SoftMail Co., Ltd | Seoul |
| Softnyx | Seoul |
| Software Property-Right Council | Seoul |
| SoftWiz | Gyeonggi |
| Sogang University | |