| SEOBank | |
| SEOCertification.org | |
| SEOFY | |
| SEOheights.com | |
| SEOLab | Ontario |
| SeoLogist | |
| Seon | British Columbia |
| SEOPlus+ | Ontario |
| SEORepublic | |
| Sepset Biosciences, Inc. | |
| sept24 communications marketing | Quebec |
| September Media Company, Inc. | Ontario |
| Sequence Bio | |
| SeQuent | Ontario |
| Seradex | Ontario |
| SeraGene Therapeutics | |
| Serene Technologies | |
| Serene-Risc | Quebec |
| Serenic Software | Alberta |
| Serenity Bioworks | |
| Serenity Power, Inc. | |
| Serge Web Service | British Columbia |
| Sergey Design | Ontario |
| Serious Labs | Alberta |
| Serious Monkey | Ontario |
| Seriously Creative | British Columbia |
| Serj Kozlov | Ontario |
| Serloc, Inc. | Quebec |
| Sernova Biotherapeutics | |
| Sernova Corporation | |
| SERTI | Quebec |
| Server Center | Alberta |
| Server North, Inc. | Ontario |
| Server Sitters, LLC | Prince Edward Island |
| Server4Sale | Ontario |
| ServerMania, Inc. | Ontario |
| Servers.ca | Ontario |
| Servicad, Inc. | Ontario |
| Service d'aide aux Néo-Canadiens | |
| Service d'Information SecureNet | Quebec |
| Service Informatique de l'acadie | |
| Service Informatique Professionnel | Quebec |
| Service Informatique Sept-îles | Quebec |
| Service M.G.S. Informatique, Inc. | |
| Service Marketer | |
| Service Réparation Informatique – J-C Gagnon | Quebec |
| Service Sphere Agency | |
| Service Technologique La Relance | Quebec |
| Service Ultratronic, Inc. | Quebec |
| Service-Tel | Ontario |