| Actúa Comunicación Corporativa | Castellón |
| Actual.cat | Valencia |
| Actualiza tu Negocio SLNE | León |
| Actualweb | Castellón |
| Acuarel | Pontevedra |
| Ad Ventures | Madrid |
| ADA Computer, S.A. | Zaragoza |
| Adapting, S.L. | Valencia |
| Adasoft, S.A. | Barcelona |
| Adatio Sistemas, S.L. | Madrid |
| AdBoosters | Asturias |
| ADC Design Agency | Barcelona |
| Addis | Valencia |
| Additio App | Girona |
| Addlink Software Científico, S.L. | Barcelona |
| Adeamatica, S.L. | Biscay |
| adeKi soluciones | Biscay |
| Adema Consultores Medioambientales, S.A. | Madrid |
| Adematica, S.L. | |
| Adequa | Valencia |
| ADI Hardware | Madrid |
| Adil Moujahid | Barcelona |
| Adimedia | Gipuzkoa |
| ADISO Servicios Informáticos | Alicante |
| ADJ Servicos | Murcia |
| ADL Biopharma, S.L.U. | León |
| ADM Comunicaciones | A Coruña |
| Adobe Spain | Barcelona |
| Adoramedia | Alicante |
| AdPime Iberia, S.L. | Barcelona |
| ADR Infor, S.L. | La Rioja |
| adSalsa | |
| ADSL Zone | Barcelona |
| Adsmurai | Barcelona |
| Adstrakt | |
| Adsystems | Barcelona |
| ADTelecom | Barcelona |
| Adur Software Productions | Gipuzkoa |
| Advanced Brain Companion Diagnostics Spain, S.L. | Barcelona |
| Advanced Computer Trading, S.L. | Madrid |
| Advanced Software Production Line, S.L. | Madrid |
| Advancing | Barcelona |
| Advantic Sistemas y Servicios, S.L. | Madrid |
| Advanved Soluciones | Valencia |
| Advento Networks, S.L. | Madrid |
| Adventus Systems Iberica, S.L. | Madrid |
| ADW Europe, S.L. | Biscay |
| AEBAN | Madrid |
| AELIX Therapeutics | Barcelona |
| Aernnova Aerospace, S.A. | Álava |