| iwan21 | Sevilla |
| IzarMicro | Biscay |
| Izertis, S.A. | Asturias |
| JAD Solucions Informàtiques, S.L. | Barcelona |
| Jaguar Path Ventures | Madrid |
| Jamgo | |
| Jarvis Sistemas Inteligentes, S.L. | Madrid |
| Java4Less.com | Valencia |
| Javier Gosende | Alicante |
| JC Informática | Madrid |
| JCC Suministros y Sistemas Informáticos, S.L. | Madrid |
| JDM Correduria de Seguros, S.L. | Barcelona |
| Jensen Technologies, S.L. | Granada |
| Jensen-Localization, S.L. | Málaga |
| Jet Computer | Madrid |
| Jevnet Online Marketing, S.L. | Madrid |
| JF Informática | Madrid |
| JM Software | Segovia |
| Jm2Informática | Valencia |
| JME Ventures | Madrid |
| JMJ - Sinbur informática, S.L. | Burgos |
| JMWebs.cat | Barcelona |
| JNF Programari | Barcelona |
| Job&Talent | Madrid |
| Job&Talent | |
| Jobers y Asociados, S.L. | Valencia |
| JobFluent | Barcelona |
| Jofemar, S.A. | Navarre |
| Johan Cruyff Institute | |
| JohnAppleman Branding Agency, S.L.U. | Madrid |
| Joppy | Barcelona |
| JoriGames.com | Barcelona |
| Josep Maria Blasco & Associats | Barcelona |
| Jovitel | Málaga |
| JP Computer Trading, S.L. | Madrid |
| JPA | Alicante |
| JS Development | Cantabria |
| JSSM | Salamanca |
| JT1-Electrónica, S.L. | Barcelona |
| Juan Carlos Pell | Barcelona |
| Jump Into Tech, S.L. | Madrid |
| Jungle-Communications | Balearic Islands |
| Junior Informatica, S.A. | Almería |
| Juniper | Balearic Islands |
| Jusan, S.A. | Madrid |
| JVS Service | Valencia |
| K-Infotec | Madrid |
| Kabel | Madrid |
| Kaikoo Gaming, S.L. | Málaga |
| Kaleidos | Madrid |