Top 10 Richest People in Ontario (2025)

Ontario, Canada’s economic powerhouse, is home to some of the wealthiest individuals in the country. From Toronto’s Bay Street billionaires to tech innovators in Waterloo and real estate tycoons in Ottawa, the province is a hub for financial services, technology, and commerce.

Here are the Top 10 Richest People in Ontario in 2025, based on Forbes data, public filings, and verified business records.

1. David Thomson & Family – $61.3 Billion

Source of Wealth: Media, Financial Services (Thomson Reuters)
Residence: Toronto, ON

David Thomson, chairman of Thomson Reuters, leads Canada’s wealthiest family. The family’s holdings also include The Globe and Mail and major investments in real estate, tech, and energy.

2. Galen Weston Jr. – $9.8 Billion

Source of Wealth: Retail (Loblaw, Shoppers Drug Mart, Weston Foods)
Residence: Toronto, ON

As CEO of George Weston Ltd., Galen Jr. oversees Canada’s largest food and drugstore chains. The Weston family dynasty also owns Holt Renfrew and is involved in luxury retail and philanthropy.

3. Joseph Tsai – $8.6 Billion (partial Ontario presence)

Source of Wealth: Alibaba, Sports Ownership
Residence: LaSalle / Toronto, ON (seasonal)

Tsai, co-founder of Alibaba, has dual Canadian ties. He owns property in Ontario and is involved in philanthropy, sports (Brooklyn Nets), and e-commerce expansion in North America.

4. Anthony von Mandl – $7.2 Billion

Source of Wealth: Alcoholic Beverages (White Claw, Mike’s Hard Lemonade)
Residence: Toronto / Vancouver, ON

Though based part-time in British Columbia, von Mandl maintains offices and investments in Toronto. His success with White Claw and Mike’s Hard transformed him into a beverage industry billionaire.

5. Mark Leonard – $6.9 Billion

Source of Wealth: Software (Constellation Software Inc.)
Residence: Toronto, ON

Founder and president of Constellation Software, Leonard quietly built one of Canada’s most successful enterprise software holding companies, acquiring hundreds of niche tech firms worldwide.

6. Bruce Flatt – $4.5 Billion

Source of Wealth: Asset Management (Brookfield Corporation)
Residence: Toronto, ON

As CEO of Brookfield, one of the world’s largest alternative asset managers, Flatt oversees trillions in assets spanning infrastructure, real estate, and renewable energy.

7. Barry Sherman (Estate) – $3.6 Billion

Source of Wealth: Pharmaceuticals (Apotex)
Residence: Toronto, ON (legacy)

The Sherman estate, following the late Barry Sherman’s death in 2017, still holds major stakes in generic pharmaceuticals and charitable foundations tied to health, science, and education in Ontario.

8. Jim Balsillie – $2.3 Billion

Source of Wealth: Technology (BlackBerry)
Residence: Waterloo, ON

Former BlackBerry co-CEO, Balsillie remains a tech icon and policy advocate in Ontario. He now focuses on innovation law, data governance, and chairs the Centre for International Governance Innovation (CIGI).

9. Heather Reisman – $2.1 Billion

Source of Wealth: Retail (Indigo Books, Investments)
Residence: Toronto, ON

Co-founder of Indigo Books & Music and widow of Gerry Schwartz (Onex Corp.), Reisman holds major influence in publishing, education, and social impact investing, especially in Toronto’s academic circles.

10. Kevin O’Leary – $1.4 Billion

Source of Wealth: Investments, Media, O’Shares ETFs
Residence: Toronto, ON

Best known as a Shark Tank investor and business commentator, O’Leary runs O’Shares Investments and has grown his fortune through ETFs, fintech, and media licensing while maintaining deep ties in Toronto.

Summary Table

Final Thoughts

Ontario’s wealthiest residents are titans of media, retail, finance, software, and innovation. Whether born in Canada or drawn by its economic opportunities, these billionaires shape Bay Street, Silicon Valley North, and Canada’s global footprint in commerce and culture.