| Digival S.n.c. | Aosta Valley |
| Digiway S.r.l. | Milan |
| DimacRed S.p.A. | Monza and Brianza |
| Dinamico S.n.c. | Vicenza |
| Dinamo | Siena |
| Dinamoweb S.r.l. | Piacenza |
| Dipharma Francis S.r.l. | |
| Dipiemme Studio S.r.l. | Mantua |
| Dishcovery | Modena |
| Distretto Tecnologico Aerospaziale S.C. a r.l. | |
| DML Computer Service | Como |
| DNAPhone S.r.l. | |
| DNArt S.r.l. | |
| Dnetware computer S.a.s. | Rome |
| DocFlow Italia S.p.A. | Milan |
| Docsity | Turin |
| DoctorApp S.r.l. | |
| Documatic | Rome |
| Dogma Systems S.r.l. | Ancona |
| Domethics S.r.l. | Turin |
| Domino S.r.l. | Turin |
| Domotica Design S.r.l. | Milan |
| Dompé farmaceutici S.p.A. | |
| Donatello Coworking Milano | Milan |
| Dooit S.r.l. | Treviso |
| DotForce S.r.l. | Milan |
| Dotvocal S.r.l. | Genoa |
| Dove.it S.r.l. | |
| Dpixel S.r.l. | Milan |
| DPV S.p.A. | |
| Dr. Modiano & Associati S.p.A. | Milan |
| Dreamscape | Lecco |
| Drivesec | Turin |
| DroneShare.club | Cagliari |
| Drop S.r.l. | Fermo |
| Drupal Italia | Rome |
| DS Pallas S.n.c. | Milan |
| DSE S.r.l. | Turin |
| DSM S.p.A. | Parma |
| DSP-Quattro | Rome |
| Dstech S.r.l. | Rome |
| DTS Consulting S.r.l. | |
| Dune Sistemi | Rome |
| dverso Studio S.r.l. | |
| DW DreamyourMind S.r.l. | Rome |
| DW Informatica S.p.A. | Verona |
| DWS Systems | Vicenza |
| Dygroup | Turin |
| Dylog Italia S.p.A. | Turin |
| e way Enterprise Business Solutions S.r.l. | |