| One Sky | Quebec |
| One Stop Communications | Ontario |
| One Vertex Dynamic Web Solutions | British Columbia |
| One9 | |
| OneCore Media | Ontario |
| OneDealOutlet Featured Deals | |
| OneDesk | Quebec |
| Oneeleven | Ontario |
| OneGigabit | British Columbia |
| OneHub Business Consulting | |
| OneIQ Corporation | |
| Oneir Solutions | Ontario |
| Oneka Technologies | Quebec |
| OneKing Telecom | Ontario |
| OneLocal | |
| OneNine Innovations | |
| OneProvider.com | Quebec |
| OneSoft Solutions, Inc. | |
| Onethirdlab | Quebec |
| OneVest Management, Inc. | |
| OneWeb Hosting | British Columbia |
| ONG Solutions | Ontario |
| OnGeek Computer Services | British Columbia |
| Onglio | Ontario |
| Ongoing Results Ltd | Ontario |
| ONI Investments, Inc. | Newfoundland and Labrador |
| Onico Solutions | Ontario |
| Onirix Services Internet | Quebec |
| Onit | |
| Onlea Enterprises, Inc. | Alberta |
| Online Authority | Ontario |
| Online Business Systems | |
| Online Data | Ontario |
| Online LIMS | |
| Online Xperts | Ontario |
| Online-learning.com | Quebec |
| onlineelectronicsinc.com | Ontario |
| OnlineKarma | Ontario |
| OnlyGrowth | |
| onPoint | |
| OnPoint ONE | British Columbia |
| OnPoint Software Training Solutions, Inc. | Ontario |
| OnRamp | |
| OnRes Systems, Inc. | British Columbia |
| OnSched | |
| OnServe | Ontario |
| ONSIDE | Nova Scotia |
| Onsight Technologies | Ontario |
| OnSite Computer Services | |
| OnSite Geeks Ltd | British Columbia |