| Adastra | |
| Adastra Corporation | Ontario |
| Adax.ca | Ontario |
| AdChat Media Technology, Inc. | |
| Adcom Solutions | Saskatchewan |
| Adcount | |
| ADCstat | |
| Addaptron Software | British Columbia |
| Addata, Inc. | |
| Addax Computer | British Columbia |
| Addere | |
| Addimark | |
| Addison Électronique | Quebec |
| AdDispenser | Ontario |
| Addisplay | |
| Additional Software, Inc. | |
| Addmore Group | Ontario |
| Adecco Employment Services Ltd | Ontario |
| Adedia, Inc. | British Columbia |
| Adelweiss Technologies | |
| Adeo Marketing | Quebec |
| Adeptmind | |
| ADFLOW Networks | Ontario |
| ADG Informatique, Inc. | Quebec |
| ADGN Consultants | Quebec |
| Adgo Interactive Ltd | |
| AdGraphics | Ontario |
| AdHawk Microsystems | |
| Adhesive Communications | Ontario |
| adHub, Inc. | |
| Adiktiv Technologies, Inc. | |
| Adin Group, Inc. | Ontario |
| ADInfo | Quebec |
| Adlan Corporation | Ontario |
| Adler Web Design | Quebec |
| Adlib | Ontario |
| AdLuge | |
| Admaco | Quebec |
| adMare Bionnovations | |
| Admark Communications & Design | Quebec |
| Admee Marketing | British Columbia |
| Adment Digital, Inc. | Ontario |
| Administration Data, Inc. | |
| Administration régionale Baie-James | |
| Adminware Corporation | Manitoba |
| ADN Communication | Quebec |
| ADN emploi | |
| Adnet Communications, Inc. | British Columbia |
| Adnetis | Quebec |
| ADNM International | Quebec |