| Astucemedia, Inc. | Quebec |
| Astus | Quebec |
| Astute Internet | British Columbia |
| Asurtec Solutions, Inc. | Ontario |
| Asyma | Alberta |
| Asynchron Systems, Inc. | Ontario |
| At The Helm | |
| Atakama Studio | Quebec |
| ATB Financial | |
| Atcom Systems, Inc. | Alberta |
| Atek Canada | Quebec |
| Ateka | |
| Atelier d'intelligence appliquée | Quebec |
| Atelier V | Quebec |
| ATEQ Canada, Inc. | Ontario |
| Aterlo Networks | Ontario |
| ATG Pharma | Ontario |
| Athabasca University | Alberta |
| Athabasca University - Faculty of Science and Technology | Alberta |
| Athabsca University - Mathematics and Statistics | Alberta |
| Athena Computer Solutions | Nova Scotia |
| Athena Software | Ontario |
| ATHENA Technolo-G, Inc. | Quebec |
| Athennian | |
| ATI Cables | Ontario |
| ATIC Computers | British Columbia |
| Atiigo Media | Nunavut |
| Atimi Software, Inc. | British Columbia |
| Atlantic BIOCON | |
| Atlantic Canada Aerospace and Defence Association | |
| Atlantic Canada Opportunities Agency | |
| Atlantic Cell Phone Repair | |
| Atlantic Computational Excellence Network | New Brunswick |
| Atlantic Electronics Ltd | Nova Scotia |
| Atlantic FinTech | Nova Scotia |
| Atlantic Institute for Resilience, Inc. | |
| Atlantic Technology Centre | |
| Atlantic Technology Summit | Nova Scotia |
| Atlantic Venture Forum | Nova Scotia |
| Atlantic Webfitters | Nova Scotia |
| atlantiq AI Automation Solutions Ltd | |
| Atlantis | |
| Atlas Agency, Inc. | Ontario |
| Atlas Micronet, Inc. | Ontario |
| AtlasTrax Communication Corporation | Ontario |
| Atleon, Inc. | Quebec |
| ATM Consulting | Ontario |
| ATM Web Design, Inc. | Ontario |
| Atmacinta | Quebec |
| Atomic 55 Internet Technologies, Inc. | |