| University of Western Ontario - Department of Mathematics | Ontario |
| University of Windsor | Ontario |
| University of Windsor - Mathematics and Statistics Department | Ontario |
| University of Windsor - School of Computer Science | Ontario |
| University of Winnipeg | Manitoba |
| University of Winnipeg - Applied Computer Science | Manitoba |
| University of Winnipeg - Mathematics and Statistics | Manitoba |
| UniversityStudy.ca | Ontario |
| UnixHQ.com | Ontario |
| Unleash Web | Ontario |
| Unlimit IT Solutions | |
| Unlimited Computers, Inc. | Newfoundland and Labrador |
| Unlimited Exposure Online | Ontario |
| UnlimitedViz | Ontario |
| Uno Platform | |
| Unoapp.com | |
| Unreal Ideas | Ontario |
| Unryo, Inc. | |
| Untether AI | Ontario |
| Unvale New Media Solutions | British Columbia |
| Unylogix Technologies, Inc. | Quebec |
| UonCloud | |
| Up Front By Design | |
| Up Your Media | British Columbia |
| Up-n-Running Computers and Networks | British Columbia |
| Upaknee | Ontario |
| Upclick, Inc. | Quebec |
| Upcycli | |
| Updata | |
| Upgrade My Site | Ontario |
| Uploadcare, Inc. | |
| UPMACS Communications, Inc. | Quebec |
| Upnorthwebs.com | Ontario |
| UpperStage.Capital | |
| Uppgroup, Inc. | British Columbia |
| Uprising Agency Canada | Alberta |
| Upside Wireless, Inc. | British Columbia |
| UpsideWave, Inc. | Ontario |
| Upstream Marketing, Inc. | Newfoundland and Labrador |
| Upstream Works Software Ltd | Ontario |
| UptimeHost.com | Ontario |
| Uptimum Informatique | Quebec |
| Uptown Communication House, Inc. | Ontario |
| Upverter | Ontario |
| UQDevices | Ontario |
| Ur Cell | Ontario |
| Uraeus | Quebec |
| URBA Media | Alberta |
| Urban Block Media | Ontario |
| Urban Communications, Inc. | British Columbia |