M3 Tops Out as Canada’s Tallest Tower Outside Toronto

Rising to 82 storeys and standing at 258 metres, M3 (the third M City tower) is now the tallest residential tower in Canada outside of Toronto. Source: EllisDon

M3 is the latest addition to the ambitious M City development, a multi-phase master-planned community that is reshaping Mississauga’s downtown core. Designed to bring new energy and density to the area, M3 blends residential, retail, and office space to foster a walkable, connected neighbourhood. Its striking silhouette adds a bold architectural statement to the skyline, while its thoughtful design supports a vibrant, inclusive urban lifestyle.

“From splash pads and sundecks to community BBQ areas and shared lounges, we’ve built a building full of amenities that are designed to bring people together,” said Neil Christian, Senior Project Manager, Buildings Group, EllisDon. “These spaces encourage connection, wellness, and a sense of belonging—key ingredients for building a thriving vertical neighbourhood.”

What truly sets M3 apart isn’t just its height or design—it’s the engineering marvel hidden near its peak. Suspended high above the city is a 705-tonne tuned mass damper (TMD), the largest of its kind in Canada. This pendulum-like device, used primarily in the supertall skyscrapers of New York City, is engineered to counteract the natural sway caused by wind. Technology like this is required in buildings as tall as M3 that are routinely exposed to strong winds.

When gusts push the tower, the TMD swings in the opposite direction, absorbing and neutralizing the motion. This ensures that residents—even those on the highest floors—experience a stable, comfortable environment. This is the first of its kind in Canada, and a defining feature that allows M3 to reach record-breaking heights without compromising livability.

Beyond comfort, the TMD plays a critical role in preserving the building’s long-term structural integrity. It’s a quiet giant working behind the scenes, safeguarding the tower’s performance and enhancing the everyday experience of those who call it home. This vision has been brought to life through the expertise and collaboration of key EllisDon teams, including Virtual Design & Construction (VDC), Oxford Builders, and Construction Sciences, whose contributions have been instrumental in shaping both the form and function of M3.