| De-Zign.net | New Brunswick |
| Deadman Consulting | Ontario |
| Dealcloser, Inc. | |
| DealerMine CRM | |
| DealMaker | |
| DealPoint | |
| Dean McNeil Creative Solutions | Nova Scotia |
| Dean's Consulting Services | Nova Scotia |
| Debolt Data Depository | Alberta |
| DeCastris Electronics | |
| Decentral, Inc. | Ontario |
| Decentralised Energy Canada | |
| Decimal | Quebec |
| Decision Software, Inc. | Ontario |
| Decision.io | Ontario |
| DecisionHub | |
| DecisioningIT Canada | |
| Decisive Artificial Intelligence, Inc. | |
| Decisive Farming | |
| Decisive Technologies | Ontario |
| Declan Whelan | Ontario |
| Decor Fusion | Ontario |
| DecoTech Pro | Quebec |
| DedicatedServers.ca | Saskatchewan |
| Dedupely Software, Inc. | |
| Deejays.com | British Columbia |
| Deep Blue Creative | British Columbia |
| Deep Dish Digital | Saskatchewan |
| Deep Genomics | |
| Deep Software, Inc. | British Columbia |
| Deep South Technologies | Ontario |
| Deep Tech Canada | |
| Deep Tech Health | |
| Deep Tech Network | |
| Deep VIsion | Nova Scotia |
| Deep-C | |
| DeepDive World | |
| Deeplite | |
| DeepMarkit | |
| DeepNet Technologies | Ontario |
| deepPIXEL, Inc. | |
| DeepSense | |
| DeepSight, Inc. | |
| DeepSpar Data Recovery Systems | Ontario |
| Deerhide Computer Services | Ontario |
| Dees Communications | Alberta |
| Deeth Williams Wall | Ontario |
| DEFAU Network Services Corporation | British Columbia |
| DEFAU Network Systems Corporation | British Columbia |
| Defence Therapeutics | |