These Toronto-based companies with in-house R&D are primarily large organizations, including several major healthcare networks and educational institutions. Among them, Thomson Reuters offers news and information tools for professionals, Celestica provides design and manufacturing solutions for various industries, and Apotex Inc. produces affordable pharmaceutical products. University of Toronto is a leading Canadian university focused on research and education.
A notable pattern among these companies is the strong presence of the healthcare sector, with organizations like University Health Network, Unity Health Toronto, and The Hospital for Sick Children dominating a significant portion of the list. This indicates a concentration of R&D efforts within medical research, patient care innovation, and health technology in Toronto.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Thomson Reutersthomsonreuters.com
It offers news and information tools for professionals in legal, regulatory, and tax sectors, helping them navigate complex environments. |
36,640 | |||
| 2 |
University of Torontodefygravitycampaign.utoronto.ca
Leading Canadian university focused on research, innovation, and global education to address pressing societal challenges and prepare students for success |
28,832 | |||
| 3 |
Celesticacelestica.com
Global leader in providing design, manufacturing, and supply chain solutions for aerospace, defense, communications, healthtech, and more, delivering innovative solutions for complex challenges |
16,022 | |||
| 4 |
University Health Networkuhn.ca
Largest Canadian research hospital network specializing in patient care, medical research, education, and fundraising for advanced healthcare services. |
11,930 | |||
| 5 |
Ontario Power Generationopg.com
Leading clean power generator advancing clean energy innovations, striving for a net-zero future with diverse electricity generation fleet in Ontario and the United States |
9,878 | |||
| 6 |
Unity Health Torontounityhealth.to
A health network in Toronto providing primary, community, specialized, and long-term care services, as well as investing in research and education |
8,686 | |||
| 7 |
The Hospital for Sick Childrensickkids.ca
Leading pediatric hospital integrating patient care, research, and education to advance children's health and develop innovative treatments globally. |
8,636 | |||
| 8 |
Toronto Metropolitan Universitytorontomu.ca
Innovative urban university in Toronto, focusing on creativity, entrepreneurship, inclusivity, and global community engagement to serve societal needs |
8,478 | |||
| 9 |
Sunnybrooksunnybrook.ca
A leading teaching hospital affiliated with the University of Toronto, specializing in patient care, groundbreaking research, and inventing the future of healthcare |
7,599 | |||
| 10 |
Apotex Inc.apotex.com
A global pharmaceutical company producing affordable high-quality medicines, with divisions focusing on generics, biosimilars, consumer products, and API manufacturing |
6,548 | |||
| 11 |
St. Michael's Hospitalunityhealth.to
A leading hospital providing compassionate care, medical education in 27 disciplines, and research through the Keenan Research Centre for global impact |
4,868 | |||
| 12 | 4,477 | ||||
| 13 |
LifeLabs Medical Laboratory Serviceslifelabs.com
A leading Canadian provider of diagnostic information and digital health systems, offering laboratory tests, genetics services, and online patient portals |
4,356 | |||
| 14 |
Sinai Healthsinaihealth.ca
A leading academic health science centre focused on integrated care, innovative research, and educating future healthcare leaders for comprehensive patient care |
4,083 | |||
| 15 |
ABC Technologiesabctechnologies.com
A global leader in plastics and injection molding technology for the automotive industry, focusing on innovation, sustainability, and creating career opportunities |
4,059 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 16 |
CSA Testing & Certificationcsagroup.org
Development of safety and technical standards combined with global testing, inspection, and certification services for diverse industries. |
3,522 | |||
| 17 |
1Password1password.com
Protects business data, employee accounts, and sensitive information with secure access, sharing, and integration into existing systems. |
3,074 | |||
| 18 |
Mount Sinai Hospital (Toronto), Sinai Healthmountsinai.on.ca
Internationally recognized academic health sciences center providing exemplary patient care, nursing excellence, and top employer culture Flagship clinical programs available |
2,951 | |||
| 19 |
Michael Garron Hospitaltehn.ca
A vibrant community hospital in East Toronto providing high-quality, patient-centred healthcare services along the continuum of care with strong partnerships |
2,219 | |||
| 20 |
FGF Brandsfgfbrands.com
Innovative technology-driven bakery pushing boundaries with sustainable ingredients, creating delicious baked goods and disrupting the global food industry for the better |
2,195 | |||
| 21 |
Give and Go Prepared Foodsgiveandgo.com
A leading manufacturer of sweet baked goods, offering indulgent treats under various brands, with a focus on innovation and quality for global retailers |
2,143 | |||
| 22 |
Colas Canada Inc.colas.com
A leading company in construction and maintenance of transportation infrastructure across Canada, part of a global group with operations worldwide |
2,065 | |||
| 23 |
Baycrestbaycrest.org
Global leader in aging and brain health innovations, offering comprehensive care for aging patients, conducting top research in cognitive neuroscience, and promoting global knowledge exchange |
1,407 | |||
| 24 |
Kinectricskinectrics.com
Integrated lifecycle management services for electric power industry worldwide Testing, inspection, certification, engineering consulting, and maintenance services to ensure safe and efficient utility asset performance |
1,361 | |||
| 25 |
OCAD Universityocadu.ca
A leading institution in Canada, specializing in art and design education for aspiring students to excel in their creative pursuits |
1,343 | |||
| 26 |
DECIEM | THE ABNORMAL BEAUTY COMPANYdeciem.com
A beauty brand umbrella offering high-quality, transparent skincare products, founded by a disrupter aiming to redefine beauty industry standards |
1,311 | |||
| 27 |
Tenstorrenttenstorrent.com
Tenstorrent builds next-generation AI computers, combining expertise in computer architecture, ASIC design, systems, and neural network compilers Offices worldwide Join our team! |
1,226 | |||
| 28 |
Armstrong Fluid Technologyarmstrongfluidtechnology.com
A global leader in intelligent fluid flow equipment and optimization technologies, focusing on HVAC, plumbing, gas transmission, and fire safety applications |
1,224 | |||
| 29 |
Women's College Hospitalwomenscollegehospital.ca
A pioneering healthcare institution focusing on women's health, innovation, and addressing Canada's healthcare challenges through interdisciplinary teams and equitable work environment |
1,200 | |||
| 30 |
Holland Bloorview Kids Rehabilitation Hospitalhollandbloorview.ca
Pioneering treatments, technologies, and programs for children with disabilities to fully participate in life through a world-class teaching hospital |
1,086 | |||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 11, 2026.
More company lists in Toronto
- The largest companies in Toronto 1,921
- Multinational companies in Toronto 377
- Financial services firms in Toronto 250
- Financial Services companies in Toronto 163
- SaaS companies in Toronto 160
- Software Development companies in Toronto 131
- Critical infrastructure operators in Toronto 120
- Professional services firms in Toronto 117
- Retail chains in Toronto 116
- Education providers in Toronto 109
- IT Services and IT Consulting companies in Toronto 100
- Companies with a mobile app in Toronto 97
- Subscription businesses in Toronto 93
- Investment Management companies in Toronto 92
- Manufacturers in Toronto 88
- Publicly traded companies in Toronto 86
- AI companies in Toronto 82
- Consulting firms in Toronto 70
- Healthcare providers in Toronto 68
- Advertising Services companies in Toronto 66
- Hospitals and Health Care companies in Toronto 66
- IT services companies in Toronto 66
- Public sector organisations in Toronto 64
- Retail companies in Toronto 61
The same list elsewhere in Canada
- Companies with in-house R&D in Canada 678
- Companies with in-house R&D in Ontario 300
- Companies with in-house R&D in the province of Quebec 159
- Companies with in-house R&D in British Columbia 76
- Companies with in-house R&D in Alberta 74
- Companies with in-house R&D in Montreal 59
- Companies with in-house R&D in Calgary 39
- Companies with in-house R&D in Vancouver 34