| Company | Industry | City |
| D-SOL Media Marketing | Burlington | |
| d3 | Toronto | |
| dailypixel.ca Network | Ottawa | |
| Darkwave Studios | Games | Mississauga |
| David Berman Communications | Ottawa | |
| David Ellis | Toronto | |
| dB Audio Inc. | E-learning and Education | Toronto |
| Decode Entertainment | Toronto | |
| Deloitte | Toronto | |
| Department of National Defence (Canadian Forces) | Borden | |
| Design Office Zen | Thornbury | |
| DesignAxiom | Toronto | |
| designguru | Toronto | |
| Desire2Learn Inc. | Kitchener-Waterloo | |
| DiBA Canada | Toronto | |
| digiBee.net | London | |
| Digital Creations Inc. | Vaughan | |
| Digital Download Game World Inc. | Toronto | |
| Digital Duck Inc. | Brantford | |
| Digital Extremes | London | |
| Digital Extremes | London | |
| Digital Fortress Corporation | Applications, Software | London |
| Digital Leisure, Inc. | Gormley | |
| Digital Means | Toronto | |
| Digital Media Professionals Association | Toronto | |
| Digital Motion Studio | TORONTO | |
| Digital North Media Inc. | Waterloo | |
| Digital Rain Inc. | Toronto | |
| Digital Wizards | Cambridge | |
| Direction Ontario | Kapuskasing | |
| Directors Guild of Canada | Toronto | |
| dominKnow Inc. | Perth | |
| Dot Internet Solutions Inc. | Toronto | |
| Dots & Pixels Inc. | Woodbridge | |
| Dougal & Co. | Toronto | |
| DPA Communications | Toronto | |
| DrinkBox Studios Inc. | Games | Toronto |
| DTK Productions Inc. | Television Production | Toronto |
| DTZ Barnicke | Toronto | |
| Dymaxium | Toronto |