| DMS Control | British Columbia |
| DMS Group | |
| DMS iTech | |
| DMS Services, Inc. | |
| DMT Bioproducts | |
| DMTI Spatial | Ontario |
| DMXReady.com | Ontario |
| DMY Business Solutions | |
| DMZ Ventures | Ontario |
| DNA Data Networking and Assemblies Ltd | British Columbia |
| DNA Genotek, Inc. | |
| DNAstack | |
| DNI Web Design | Saskatchewan |
| DNSnetworks | Ontario |
| Do Gooders | |
| Do Process Software Ltd | Ontario |
| Doc Clik | |
| Doc PC | Ontario |
| DocBis, Inc. | |
| DocBoss.com | Alberta |
| Docebo, Inc. | |
| DOCFOCUS | Alberta |
| Docimage, Inc. | Quebec |
| Dockit | |
| Dockridge Digital, Inc. | |
| Docom | Quebec |
| DOCOVA | Ontario |
| Doctalk | |
| Docteur Phone | |
| DocteurDirect.com | Quebec |
| Doctor Dan | Ontario |
| Doctor Dave Computer Remedies | Ontario |
| Doctor PC | Ontario |
| Doctr | |
| Docu-Type | Ontario |
| Docucomm | |
| DOCUdavit Solutions, Inc. | Ontario |
| DocuFire | Ontario |
| Document Conversion Engine | British Columbia |
| Document Imaging Partners | Ontario |
| Dodge Data & Analytics | British Columbia |
| Dodge Ink, Inc. | Ontario |
| DOFACS | Ontario |
| Dog and Pony Studios | Ontario |
| Dog Park Software Ltd | Ontario |
| Dok-Tor Harddrive | Alberta |
| Dok2U | |
| Dolce | Quebec |
| DollarHost | British Columbia |
| Dolomite Networks | Ontario |