| Tornado | |
| Tornatech | |
| Toronix Engineering Corporation | Ontario |
| Toronto Agile Software Development Community | Ontario |
| Toronto Business Communications, Inc. | Ontario |
| Toronto Business Development Centre | |
| Toronto Cabling Solutions | Ontario |
| Toronto Computuer Repair Services | Ontario |
| Toronto Delphi Users Group | Ontario |
| Toronto Digital | Ontario |
| Toronto Digital Analytics | |
| Toronto E-Commerce | Ontario |
| Toronto Fashion Incubator | Ontario |
| Toronto Free‑Net | Ontario |
| Toronto Game Jam | Ontario |
| Toronto Global | Ontario |
| Toronto Innovation College | |
| Toronto Institute of Pharmaceutical Technology | |
| Toronto Metropolitan University | Ontario |
| Toronto Metropolitan University - Centre for Urban Energy | Ontario |
| Toronto Metropolitan University - Department of Computer Science | Ontario |
| Toronto Metropolitan University - Design Fabrication Zone | Ontario |
| Toronto Metropolitan University - Legal Innovation Zone | Ontario |
| Toronto Metropolitan University - Science Discovery Zone | Ontario |
| Toronto Metropolitan University - Social Ventures Zone | Ontario |
| Toronto Microelectronics, Inc. | Ontario |
| Toronto Oracle Users Group | Ontario |
| Toronto PET User's Group | Ontario |
| Toronto School of Management | |
| Toronto SEO and Marketing Corporation | Ontario |
| Toronto SEO Firm | Ontario |
| Toronto Surplus & Scientific, Inc. | Ontario |
| Toronto Tech Company | Ontario |
| Toronto Users Group | Ontario |
| Toronto Web Hosting | Ontario |
| TorontoCabling | Ontario |
| TorontoStarts | Ontario |
| TORQ IT Ltd | |
| Torrent Capital | |
| Torrie Smith Associates, Inc. | Ontario |
| TortoiseCVS | Ontario |
| Torus Power | Ontario |
| Torusoft | Nova Scotia |
| Toshiba TEC Canada Business Solutions, Inc. | Ontario |
| tossdown, Inc. | |
| Total e Work | Ontario |
| Total Internet Marketing | Ontario |
| Total North Communications | Yukon |
| Total Project Logistics | Quebec |
| Total Quality Management Systems | Ontario |