| SBA Informática | Valencia |
| SBSS Consulting, S.A. | Barcelona |
| SC Trade Technologies | Barcelona |
| Scaled Robotics | Barcelona |
| Scalian Spain | Madrid |
| Scan96 | Madrid |
| Scati Labs, S.A. | Zaragoza |
| SCImago | |
| Scoreapps | Madrid |
| Scytl Election Technologies, S.L.U. | Barcelona |
| Scytl Secure Electronic Voting, S.A. | Barcelona |
| SDi Digital Group | La Rioja |
| Sea and Air Technology, S.L. | Madrid |
| Seabery | Huelva |
| Seaya | |
| Seaya Ventures | Madrid |
| Secel Tecnològics, S.L. | Barcelona |
| Secíber Hardfrank, S.L. | Badajoz |
| Secret Source Technology, S.L. | |
| Secuoyas | Madrid |
| SEDDI | Madrid |
| Seed&Click | Barcelona |
| SeedRocket | Barcelona |
| Seedtag | Madrid |
| SEGA Saturno | Barcelona |
| Seglan | Madrid |
| SegoFinance | Madrid |
| SEINCO Servicios de Informática y Comunicaciones, S.L. | Salamanca |
| SEIS INFORMÁTICA, S.L. | Valencia |
| Sek Lab Awards | Madrid |
| Sekuenz | |
| Selekron Microcontrol, S.L. | Guadalajara |
| Semantic Web Software, S.L. | Sevilla |
| SEMIC | Lleida |
| Semiconductores y Sistemas, S.A. | Barcelona |
| Semidynamics | |
| Semilla Proyectos, S.L. | Asturias |
| Señor Muñoz | Madrid |
| Sensornor Aplicaciones Electrónicas, S.L. | Biscay |
| Sentido Comun Internet, S.L. | Asturias |
| Séntisis Intelligence | Málaga |
| Seo Asesor | León |
| SEO Barcelona | Barcelona |
| Seo In House | Barcelona |
| SEO León | |
| SEO Natural, S.L. | A Coruña |
| Seocom | Barcelona |
| SEOInnova | |
| Seolocalygoogleads | |
| SeoManiak | Barcelona |