| Jevnet Online Marketing, S.L. | Madrid |
| JF Informática | Madrid |
| JIG | |
| JM Software | Segovia |
| Jm2Informática | Valencia |
| JME Ventures | Madrid |
| JMJ - Sinbur informática, S.L. | Burgos |
| JMWebs.cat | Barcelona |
| JNF Programari | Barcelona |
| Job&Talent | Madrid |
| Jobers y Asociados, S.L. | Valencia |
| JobFluent | Barcelona |
| Jofemar, S.A. | Navarre |
| Johan Cruyff Institute | |
| JohnAppleman Branding Agency, S.L.U. | Madrid |
| Jolt Solutions | |
| Joppy | Barcelona |
| Jorge Pozo | |
| JoriGames.com | Barcelona |
| José Roldán | |
| 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 |
| Kanlli | Madrid |
| Kanoar Ventures, S.G.E.I.C, S.A. | Valencia |
| Kantaronet.com | A Coruña |
| Kanteron Systems, S.L.U. | Valencia |
| Kantox Ltd | Barcelona |
| Kanzen Design | Madrid |
| Karakana Factoría TIC, S.L. | Pontevedra |
| Karten Space | |
| KaukaVR | Gipuzkoa |
| Kedu Cooperativa | Barcelona |
| Keepler Data Tech, S.L. | |
| KeepMeReady, S.L. | Murcia |