| Cyology Labs | |
| Cyper | British Columbia |
| CYPFER | |
| Cypher Consulting | British Columbia |
| Cypher Systems | Ontario |
| Cypress Solutions | British Columbia |
| Cyprex | Quebec |
| Cyr Système | Quebec |
| Cyrod Technologies, Inc. | Ontario |
| Cyrux Smart Solutions, Inc. | Ontario |
| Cysca Technologies | Quebec |
| D S Computer Services | British Columbia |
| D&A Business Management Solutions | Ontario |
| D&K Computers and Crafts | |
| D-BOX | Quebec |
| D-Link Canada | Ontario |
| D-Mack Media | British Columbia |
| D-Modules, Inc. | Quebec |
| D-SOL Media, Inc. | Ontario |
| D-Tech Consulting | Ontario |
| D-Type Solutions | Ontario |
| D-Wave Systems | British Columbia |
| D.C. Computers, Inc. | Ontario |
| D.C. Planet Computers | British Columbia |
| D.C.S. Technologies | British Columbia |
| D.E. Systems Ltd | Ontario |
| D.L.G.L. Ltd | Quebec |
| D.Y.M. Communication, Inc. | New Brunswick |
| d1g1t | |
| D2C Media | Quebec |
| D2L Corporation | Ontario |
| D2R Collect | |
| D3DGear Technologies | Ontario |
| DA Global Consultants, Inc. | Ontario |
| DA-Integrated | Ontario |
| DAC Group | Ontario |
| Dacima Software, Inc. | Quebec |
| Dacom Technical Services, Inc. | Ontario |
| Dacris Software | Ontario |
| Dadavan Systems, Inc. | |
| Daemon Defense Systems | Manitoba |
| Dafe Software | |
| Dafocom Solutions, Inc. | Ontario |
| Dafran, Inc. | |
| Daganova Solutions | |
| Daily Delivery | British Columbia |
| Daisy Intelligence | Ontario |
| Daiwa Distribution, Inc. | Ontario |
| Dakis Decision Systems, Inc. | Quebec |
| Dakota Analytics, Inc. | Alberta |