# List of companies with in-house R&D in Ontario

Tamtam tracks 300 companies with in-house R&D headquartered in Ontario. This list ranks the 100 largest by number of employees on LinkedIn, led by Magna International, Thomson Reuters and University of Toronto. Their median headcount is 2,322. Half of them were founded in 1973 or later. The most common headquarters are Toronto (37), Ottawa (11) and Mississauga (7).

This selection of companies in Ontario highlights organizations with substantial in-house R&D capabilities, primarily large enterprises and institutions. It features major players across several sectors, including Magna International, which develops technologies for safer and cleaner vehicles; Thomson Reuters, providing information tools for legal and tax professionals; Shopify, offering e-commerce solutions; and OpenText, specializing in information management. The list also includes prominent educational and healthcare institutions like the University of Toronto and University Health Network.

A notable pattern among these R&D-focused entities is the strong presence of Toronto as a headquarters city, alongside other key locations such as Ottawa, Aurora, and Waterloo. This suggests a concentration of research and development activities within the province's major urban centers, spanning manufacturing, software development, higher education, and healthcare.

🇨🇦 Ontario · 100 companies · Updated Nov 12, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Magna International](https://www.tamtam.ai/c/magna-international) (magna.com)<br>Developing technologies and systems to make vehicles safer and cleaner, focusing on community, environmental, and human benefits. | Motor Vehicle Manufacturing | 🇨🇦 Aurora | 158,000 | 1957 |
| 2 | [Thomson Reuters](https://www.tamtam.ai/c/thomson-reuters) (thomsonreuters.com)<br>It offers news and information tools for professionals in legal, regulatory, and tax sectors, helping them navigate complex environments. | Software Development | 🇨🇦 Toronto | 36,640 |  |
| 3 | [University of Toronto](https://www.tamtam.ai/c/university-of-toronto) (defygravitycampaign.utoronto.ca)<br>Leading Canadian university focused on research, innovation, and global education to address pressing societal challenges and prepare students for success | Higher Education | 🇨🇦 Toronto | 28,832 |  |
| 4 | [Shopify](https://www.tamtam.ai/c/shopify) (shopify.com)<br>Provides trusted tools to start, grow, market, and manage a retail business of any size, powering millions of businesses across 175 countries. | Software Development | 🇨🇦 Ottawa | 28,526 | 2006 |
| 5 | [OpenText](https://www.tamtam.ai/c/opentext) (opentext.com)<br>It specializes in Information Management, assisting businesses of all sizes in securely capturing, governing, and exchanging information globally. | Software Development | 🇨🇦 Waterloo | 22,990 | 1991 |
| 6 | [Celestica](https://www.tamtam.ai/c/celestica) (celestica.com)<br>Global leader in providing design, manufacturing, and supply chain solutions for aerospace, defense, communications, healthtech, and more, delivering innovative solutions for complex challenges | Technology, Information and Internet | 🇨🇦 Toronto | 16,022 | 1994 |
| 7 | [University of Ottawa](https://www.tamtam.ai/c/university-of-ottawa) (uottawa.ca)<br>The company is the largest bilingual university in the world, offering education in English and French with a focus on research and global advancements | Higher Education | 🇨🇦 Ottawa | 12,220 |  |
| 8 | [University Health Network](https://www.tamtam.ai/c/university-health-network) (uhn.ca)<br>Largest Canadian research hospital network specializing in patient care, medical research, education, and fundraising for advanced healthcare services. | Hospitals and Health Care | 🇨🇦 Toronto | 11,930 |  |
| 9 | [Ontario Power Generation](https://www.tamtam.ai/c/ontario-power-generation) (opg.com)<br>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 | Utilities | 🇨🇦 Toronto | 9,878 | 1999 |
| 10 | [Unity Health Toronto](https://www.tamtam.ai/c/unity-health-toronto) (unityhealth.to)<br>A health network in Toronto providing primary, community, specialized, and long-term care services, as well as investing in research and education | Hospitals and Health Care | 🇨🇦 Toronto | 8,686 | 2017 |
| 11 | [The Hospital for Sick Children](https://www.tamtam.ai/c/the-hospital-for-sick-children) (sickkids.ca)<br>Leading pediatric hospital integrating patient care, research, and education to advance children's health and develop innovative treatments globally. | Hospitals and Health Care | 🇨🇦 Toronto | 8,636 | 1875 |
| 12 | [Toronto Metropolitan University](https://www.tamtam.ai/c/toronto-metropolitan-university) (torontomu.ca)<br>Innovative urban university in Toronto, focusing on creativity, entrepreneurship, inclusivity, and global community engagement to serve societal needs | Higher Education | 🇨🇦 Toronto | 8,478 |  |
| 13 | [University of Guelph](https://www.tamtam.ai/c/university-of-guelph) (uoguelph.ca)<br>Dedicated to improving quality of life through innovative research and education in essential areas like water, food, health, and environment | Higher Education | 🇨🇦 Guelph | 7,725 | 1964 |
| 14 | [The Ottawa Hospital](https://www.tamtam.ai/c/the-ottawa-hospital) (ottawahospital.on.ca)<br>Innovative teaching and research hospital providing specialized care, developing new treatments, and improving patient care through community engagement and global impact | Hospitals and Health Care | 🇨🇦 Ottawa | 7,679 | 1998 |
| 15 | [Sunnybrook](https://www.tamtam.ai/c/sunnybrook) (sunnybrook.ca)<br>A leading teaching hospital affiliated with the University of Toronto, specializing in patient care, groundbreaking research, and inventing the future of healthcare | Hospitals and Health Care | 🇨🇦 Toronto | 7,599 | 1948 |
| 16 | [London Health Sciences Centre (LHSC)](https://www.tamtam.ai/c/london-health-sciences-centre-lhsc) (lhsc.on.ca)<br>Acute care teaching hospital offering specialized clinical services, leading in discovery and innovation, providing exceptional patient care and training healthcare professionals | Hospitals and Health Care | 🇨🇦 London | 7,092 |  |
| 17 | [Hamilton Health Sciences](https://www.tamtam.ai/c/hamilton-health-sciences) (hamiltonhealthsciences.ca)<br>Healthcare organization delivering specialized cardiac, stroke, trauma, cancer, palliative, and pediatric care to southwestern Ontario and beyond. | Hospitals and Health Care | 🇨🇦 Hamilton | 6,690 |  |
| 18 | [Linamar Corporation](https://www.tamtam.ai/c/linamar-corporation) (linktr.ee)<br>Advanced manufacturing company specializing in solutions for vehicles, motion, work, and lives Comprised of Industrial and Mobility segments, with global reach and innovative products | Motor Vehicle Manufacturing | 🇨🇦 Guelph | 6,668 | 1966 |
| 19 | [Apotex Inc.](https://www.tamtam.ai/c/apotex-inc) (apotex.com)<br>A global pharmaceutical company producing affordable high-quality medicines, with divisions focusing on generics, biosimilars, consumer products, and API manufacturing | Pharmaceutical Manufacturing | 🇨🇦 Toronto | 6,548 |  |
| 20 | [Martinrea International](https://www.tamtam.ai/c/martinrea-international) (martinrea.com)<br>Global automotive supplier focused on metal forming, aluminum casting, fluid systems, and assemblies to meet lightweight requirements Employs 18,000 people worldwide | Motor Vehicle Manufacturing | 🇨🇦 Vaughan | 5,692 | 2001 |
| 21 | [Fisheries and Oceans Canada / Pêches et Océans Canada](https://www.tamtam.ai/c/fisheries-and-oceans-canada-peches-et-oceans-canada) (dfo-mpo.gc.ca)<br>Manage fisheries and aquaculture sustainably, protect aquatic ecosystems, maintain navigable waterways, and respond to maritime emergencies with Indigenous collaboration. | Government Administration | 🇨🇦 Ottawa | 5,665 |  |
| 22 | [ATS Corporation](https://www.tamtam.ai/c/ats-corporation) (atsautomation.com)<br>A manufacturing solutions provider with global capabilities, specializing in custom automation systems for industries such as life sciences, food & beverage, transportation, and energy | Automation Machinery Manufacturing | 🇨🇦 Cambridge | 5,287 | 1978 |
| 23 | [Conestoga College](https://www.tamtam.ai/c/conestoga-college-kitchener) (conestogac.on.ca)<br>career-focused education, training, applied research, technology-enhanced learning, co-op opportunities, and comprehensive student support for diverse learners. | Higher Education | 🇨🇦 Kitchener | 5,198 | 1967 |
| 24 | [Sheridan College](https://www.tamtam.ai/c/sheridan-college) (sheridancollege.ca)<br>Established in 1967, this institution has grown to become a leading Ontario postsecondary institution with four campuses and a diverse range of programs | Higher Education | 🇨🇦 Oakville | 5,079 | 1967 |
| 25 | [St. Michael's Hospital](https://www.tamtam.ai/c/st-michael-s-hospital) (unityhealth.to)<br>A leading hospital providing compassionate care, medical education in 27 disciplines, and research through the Keenan Research Centre for global impact | Hospitals and Health Care | 🇨🇦 Toronto | 4,868 | 1892 |
| 26 | [Natural Resources Canada (NRCan)](https://www.tamtam.ai/c/natural-resources-canada-nrcan) (natural-resources.canada.ca)<br>A department of the Government of Canada focused on advancing sustainable resource management, economic growth, and environmental stewardship through innovative policies and programs | Government Administration | 🇨🇦 Ottawa | 4,579 |  |
| 27 | [MDA Space](https://www.tamtam.ai/c/mda-space) (mda.space)<br>Global leader providing robotics, communications satellites, geointelligence, and space exploration infrastructure through engineering excellence for defense and commercial missions across the world. | Defense and Space Manufacturing | 🇨🇦 Brampton | 4,478 | 1969 |
| 28 | [CAMH](https://www.tamtam.ai/c/camh) (camh.ca)<br>A leading teaching hospital in Canada focused on transforming lives through clinical care, research, education, and advocacy for mental health and addiction issues | Hospitals and Health Care | 🇨🇦 Toronto | 4,477 | 1998 |
| 29 | [LifeLabs Medical Laboratory Services](https://www.tamtam.ai/c/lifelabs-medical-laboratory-services) (lifelabs.com)<br>A leading Canadian provider of diagnostic information and digital health systems, offering laboratory tests, genetics services, and online patient portals | Hospitals and Health Care | 🇨🇦 Toronto | 4,356 |  |
| 30 | [William Osler Health System](https://www.tamtam.ai/c/william-osler-health-system) (williamoslerhs.ca)<br>Health system with three hospitals serving 13 million residents, providing a wide range of services including inpatient, outpatient, urgent care, and specialty clinics | Hospitals and Health Care | 🇨🇦 Brampton | 4,350 |  |
| 31 | [University of Windsor](https://www.tamtam.ai/c/university-of-windsor) (uwindsor.ca)<br>A student-focused university offering undergraduate and graduate programs, professional schools, and innovative research facilities, promoting diversity and excellence in education | Higher Education | 🇨🇦 Windsor | 4,284 |  |
| 32 | [Sinai Health](https://www.tamtam.ai/c/sinai-health) (sinaihealth.ca)<br>A leading academic health science centre focused on integrated care, innovative research, and educating future healthcare leaders for comprehensive patient care | Hospitals and Health Care | 🇨🇦 Toronto | 4,083 |  |
| 33 | [ABC Technologies](https://www.tamtam.ai/c/abc-technologies) (abctechnologies.com)<br>A global leader in plastics and injection molding technology for the automotive industry, focusing on innovation, sustainability, and creating career opportunities | Motor Vehicle Manufacturing | 🇨🇦 Toronto | 4,059 | 1974 |
| 34 | [Lakeridge Health](https://www.tamtam.ai/c/lakeridge-health) (lakeridgehealth.on.ca)<br>A comprehensive healthcare provider with multiple hospitals, specialty centers, and community services, committed to delivering high-quality care to the region | Hospitals and Health Care | 🇨🇦 Ajax | 3,760 | 1998 |
| 35 | [CSA Testing & Certification](https://www.tamtam.ai/c/csa-testing-and-certification) (csagroup.org)<br>Development of safety and technical standards combined with global testing, inspection, and certification services for diverse industries. | Public Safety | 🇨🇦 Toronto | 3,522 | 1919 |
| 36 | [Durham College](https://www.tamtam.ai/c/durham-college) (durhamcollege.ca)<br>Durham College offers full-time and part-time programs in various disciplines to over 12,000 students, including a new health care technology management degree program | Higher Education | 🇨🇦 Oshawa | 3,210 | 1967 |
| 37 | [Geotab](https://www.tamtam.ai/c/geotab) (geotab.com)<br>Provides connected vehicle, asset management solutions. Leverages data analytics, AI to transform fleet performance, operations, reducing costs, driving efficiency for over 55,000 customers. | Software Development | 🇨🇦 Oakville | 3,167 | 2000 |
| 38 | [ArcelorMittal Dofasco](https://www.tamtam.ai/c/arcelormittal-dofasco) (dofasco.arcelormittal.com)<br>Leading manufacturer in North America's supply chain, producing sustainable steel products for automotive, energy, packaging, and construction industries, prioritizing employees and community engagement | Mining | 🇨🇦 Hamilton | 3,136 |  |
| 39 | [1Password](https://www.tamtam.ai/c/1password) (1password.com)<br>Protects business data, employee accounts, and sensitive information with secure access, sharing, and integration into existing systems. | Computer and Network Security | 🇨🇦 Toronto | 3,074 | 2005 |
| 40 | [St. Joseph's Healthcare Hamilton](https://www.tamtam.ai/c/st-joseph-s-healthcare-hamilton) (stjoes.ca)<br>A values-based academic health science centre affiliated with McMaster University and Mohawk College, committed to providing integrated, compassionate care and advancing research and education | Hospitals and Health Care | 🇨🇦 Hamilton | 2,983 | 1890 |
| 41 | [Conestoga College](https://www.tamtam.ai/c/conestoga-college) (on.ca)<br>A leader in polytechnic education offering career-focused programs, engineering degrees, and support services while promoting economic prosperity and student success | Higher Education | 🇨🇦 Kitchener | 2,968 |  |
| 42 | [Mount Sinai Hospital (Toronto), Sinai Health](https://www.tamtam.ai/c/mount-sinai-hospital-toronto-sinai-health) (mountsinai.on.ca)<br>Internationally recognized academic health sciences center providing exemplary patient care, nursing excellence, and top employer culture Flagship clinical programs available | Hospitals and Health Care | 🇨🇦 Toronto | 2,951 | 1923 |
| 43 | [North York General Hospital](https://www.tamtam.ai/c/north-york-general-hospital) (nygh.on.ca)<br>A leading community academic hospital in Canada offering a wide range of acute, ambulatory, and long-term care services with a focus on patient- and family-centered care | Hospitals and Health Care | 🇨🇦 North York | 2,917 | 1968 |
| 44 | [SE Health](https://www.tamtam.ai/c/se-health) (sehc.com)<br>A not-for-profit social enterprise providing knowledge, care, and support to help clients achieve health and wellbeing goals Serving over 20,000 Canadians daily | Hospitals and Health Care | 🇨🇦 Markham | 2,851 | 1908 |
| 45 | [Kingston Health Sciences Centre](https://www.tamtam.ai/c/kingston-health-sciences-centre) (kingstonhsc.ca)<br>Top Canadian hospital, advancing health care through patient care, medical research, and training future healthcare professionals for Southeastern Ontario. | Hospitals and Health Care | 🇨🇦 Kingston | 2,793 | 1849 |
| 46 | [CHEO](https://www.tamtam.ai/c/cheo) (cheo.on.ca)<br>A global leader in pediatric health care and research, providing excellence in complex care, education, and community partnership for children and youth | Hospitals and Health Care | 🇨🇦 Ottawa | 2,784 | 1974 |
| 47 | [Niagara College](https://www.tamtam.ai/c/niagara-college) (niagaracollege.ca)<br>Leader in applied education and training, established in 1967 in Welland and now expanding across the Niagara region for top student satisfaction | Higher Education | 🇨🇦 Welland | 2,686 | 1967 |
| 48 | [Multimatic](https://www.tamtam.ai/c/multimatic) (multimatic.com)<br>A global enterprise specializing in supplying automotive components, systems, and engineering services with manufacturing divisions and engineering facilities worldwide | Motor Vehicle Manufacturing | 🇨🇦 Markham | 2,598 | 1984 |
| 49 | [Canadian Nuclear Laboratories](https://www.tamtam.ai/c/canadian-nuclear-laboratories) (cnl.ca)<br>A leading organization in nuclear science and technology, specializing in research, development, engineering, waste management, and decommissioning services for various applications | Research Services | 🇨🇦 Chalk River | 2,340 | 2014 |
| 50 | [Kinaxis](https://www.tamtam.ai/c/kinaxis) (kinaxis.com)<br>Empowering businesses to orchestrate their entire supply chain network, from long-term planning to real-time execution and delivery. | Software Development | 🇨🇦 Ottawa | 2,322 |  |
| 51 | [Woodbridge](https://www.tamtam.ai/c/woodbridge) (woodbridgegroup.com)<br>Global provider of innovative solutions for automotive, commercial, recreational, packaging, healthcare, and building industries with headquarters in Canada and the USA | Motor Vehicle Manufacturing | 🇨🇦 Mississauga | 2,262 | 1978 |
| 52 | [Canadian Solar Inc.](https://www.tamtam.ai/c/canadian-solar-inc) (csisolar.com)<br>Global manufacturer of photovoltaic modules and inverters developing utility-scale solar power and battery energy storage projects with over 165 GW delivered worldwide. | Renewable Energy Semiconductor Manufacturing | 🇨🇦 Kitchener | 2,240 | 2001 |
| 53 | [Lallemand](https://www.tamtam.ai/c/lallemand) (lallemandplantcare.com)<br>A global leader in yeast and bacterial products, focusing on natural fermentation processes in agri-food industries, with opportunities for growth and innovation | Food and Beverage Manufacturing | 🇨🇦 Rexdale | 2,232 |  |
| 54 | [SOTI](https://www.tamtam.ai/c/soti) (soti.net)<br>Global provider of enterprise software solutions for mobile operations, offering a comprehensive platform for managing various devices and building mobile apps | Software Development | 🇨🇦 Mississauga | 2,224 | 1995 |
| 55 | [Michael Garron Hospital](https://www.tamtam.ai/c/michael-garron-hospital) (tehn.ca)<br>A vibrant community hospital in East Toronto providing high-quality, patient-centred healthcare services along the continuum of care with strong partnerships | Hospitals and Health Care | 🇨🇦 Toronto | 2,219 | 1929 |
| 56 | [FGF Brands](https://www.tamtam.ai/c/fgf-brands) (fgfbrands.com)<br>Innovative technology-driven bakery pushing boundaries with sustainable ingredients, creating delicious baked goods and disrupting the global food industry for the better | Food and Beverage Manufacturing | 🇨🇦 Toronto | 2,195 | 2004 |
| 57 | [Royal Victoria Regional Health Centre](https://www.tamtam.ai/c/royal-victoria-regional-health-centre) (rvh.on.ca)<br>Healthcare institution in Barrie, Ontario serving over 450,000 residents with specialized services like interventional radiology, stroke care, trauma, cancer, heart, child, and youth programs | Hospitals and Health Care | 🇨🇦 Barrie | 2,191 | 1897 |
| 58 | [Give and Go Prepared Foods](https://www.tamtam.ai/c/give-and-go-prepared-foods) (giveandgo.com)<br>A leading manufacturer of sweet baked goods, offering indulgent treats under various brands, with a focus on innovation and quality for global retailers | Food and Beverage Manufacturing | 🇨🇦 Toronto | 2,143 | 1989 |
| 59 | [IPEX by Aliaxis](https://www.tamtam.ai/c/ipex-by-aliaxis) (ipexna.com)<br>The company prioritizes honesty, fairness, integrity, and customer satisfaction through a customer-first culture, innovation, and long-term thinking in business | Wholesale Building Materials | 🇨🇦 Oakville | 2,085 | 1992 |
| 60 | [Colas Canada Inc.](https://www.tamtam.ai/c/colas-canada-inc) (colas.com)<br>A leading company in construction and maintenance of transportation infrastructure across Canada, part of a global group with operations worldwide | Construction | 🇨🇦 Toronto | 2,065 |  |
| 61 | [Magellan Aerospace Limited](https://www.tamtam.ai/c/magellan-aerospace-limited) (magellan.aero)<br>Designs and manufactures aeroengine and aerostructure components, advanced military and space products, plus engine repair and overhaul services globally. | Aviation and Aerospace Component Manufacturing | 🇨🇦 Mississauga | 2,050 |  |
| 62 | [BlackBerry](https://www.tamtam.ai/c/blackberry) (blackberry.com)<br>Provides intelligent software and services to enterprises and governments, enabling transformative applications, new revenue streams, and innovative business models with safety, security, and reliability. | Software Development | 🇨🇦 Waterloo | 2,005 |  |
| 63 | [Petro-Canada Lubricants](https://www.tamtam.ai/c/petro-canada-lubricants) (petrocanadalubricants.com)<br>The company supplies over 350 high-performance lubricants, fluids, and greases worldwide, catering to a variety of industries and applications to optimize equipment performance and reliability | Oil and Gas | 🇨🇦 Mississauga | 1,799 |  |
| 64 | [Huawei Canada](https://www.tamtam.ai/c/huawei-canada) (consumer.huawei.com)<br>A global provider of ICT infrastructure and smart devices, committed to connecting the world through innovative research and development in Canada | Telecommunications | 🇨🇦 Markham | 1,758 | 1987 |
| 65 | [Health Sciences North/Horizon Santé-Nord](https://www.tamtam.ai/c/health-sciences-north-horizon-sante-nord) (hsnsudbury.ca)<br>An integrated network providing high-quality patient care, research, teaching, and services in various medical specialties to communities in Northern Ontario | Hospitals and Health Care | 🇨🇦 Sudbury | 1,755 |  |
| 66 | [Plasman](https://www.tamtam.ai/c/plasman) (plasman.com)<br>Global leader in automotive components, offering single-source solutions for tooling, injection molding, chroming, and assembly with a collaborative mindset and unrivaled dedication | Motor Vehicle Manufacturing | 🇨🇦 Oldcastle | 1,751 | 1978 |
| 67 | [Fleming College](https://www.tamtam.ai/c/fleming-college) (flemingcollege.ca)<br>Fleming College offers personalized learning and support in various fields, fostering innovation and sustainability for students, communities, and the environment | Education Administration Programs | 🇨🇦 Peterborough | 1,746 | 1967 |
| 68 | [St. Joseph's Health Care London](https://www.tamtam.ai/c/st-joseph-s-health-care-london) (sjhc.london.on.ca)<br>A leading academic health care organization in Canada providing compassionate care, teaching, and research to help people live life fully | Hospitals and Health Care | 🇨🇦 London | 1,707 | 1869 |
| 69 | [Lambton College](https://www.tamtam.ai/c/lambton-college) (lambtoncollege.ca)<br>Provincial leader in education, training, and research, aligning programs with industry needs to provide students with experiential learning opportunities for success | Higher Education | 🇨🇦 Sarnia | 1,701 | 1966 |
| 70 | [Thunder Bay Regional Health Sciences Centre](https://www.tamtam.ai/c/thunder-bay-regional-health-sciences-centre) (tbrhsc.net)<br>An academic health sciences centre providing comprehensive care, medical research, and training for healthcare providers in a region the size of France | Hospitals and Health Care | 🇨🇦 Thunder Bay | 1,655 |  |
| 71 | [Ross Video](https://www.tamtam.ai/c/ross-video) (rossvideo.com)<br>Designs and manufactures innovative live production equipment used globally by broadcasters, sports venues, government, and production companies. | Broadcast Media Production and Distribution | 🇨🇦 Iroquois | 1,614 | 1973 |
| 72 | [IMAX](https://www.tamtam.ai/c/imax) (imax.com)<br>An entertainment technology company specializing in motion-picture technologies, large-format presentations, immersive theater experiences, and partnerships with top filmmakers worldwide | Entertainment Providers | 🇨🇦 Mississauga | 1,450 | 1967 |
| 73 | [Evertz](https://www.tamtam.ai/c/evertz) (evertz.com)<br>Leading global manufacturer of broadcast equipment and solutions for content creation, distribution, and delivery across various platforms and sectors worldwide. | Broadcast Media Production and Distribution | 🇨🇦 Burlington | 1,436 | 1966 |
| 74 | [Baycrest](https://www.tamtam.ai/c/baycrest) (baycrest.org)<br>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 | Hospitals and Health Care | 🇨🇦 Toronto | 1,407 | 1918 |
| 75 | [Kinectrics](https://www.tamtam.ai/c/kinectrics) (kinectrics.com)<br>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 | Utilities | 🇨🇦 Toronto | 1,361 | 1912 |
| 76 | [OCAD University](https://www.tamtam.ai/c/ocad-university) (ocadu.ca)<br>A leading institution in Canada, specializing in art and design education for aspiring students to excel in their creative pursuits | Higher Education | 🇨🇦 Toronto | 1,343 | 1876 |
| 77 | [DECIEM \| THE ABNORMAL BEAUTY COMPANY](https://www.tamtam.ai/c/deciem-the-abnormal-beauty-company) (deciem.com)<br>A beauty brand umbrella offering high-quality, transparent skincare products, founded by a disrupter aiming to redefine beauty industry standards | Research Services | 🇨🇦 Toronto | 1,311 | 2013 |
| 78 | [Bruyère Health](https://www.tamtam.ai/c/bruyere-health) (bruyere.org)<br>The company provides a range of health care services including rehabilitation, complex care, family health teams, long-term care, and senior living options Their mission is to enhance quality of life through integrated care | Hospitals and Health Care | 🇨🇦 Ottawa | 1,298 | 1845 |
| 79 | [D2L](https://www.tamtam.ai/c/d2l) (d2l.com)<br>Provides learning platforms for all ages, supports millions online and in person, makes technology more human for education globally. | E-Learning Providers | 🇨🇦 Kitchener | 1,271 | 1999 |
| 80 | [General Dynamics Mission Systems–Canada](https://www.tamtam.ai/c/general-dynamics-mission-systems-canada) (gdmissionsystems.ca)<br>A leading Canadian defense and security technology organization, focused on innovation, community involvement, and supporting military needs worldwide | Defense and Space Manufacturing | 🇨🇦 Ottawa | 1,270 |  |
| 81 | [Tenstorrent](https://www.tamtam.ai/c/tenstorrent) (tenstorrent.com)<br>Tenstorrent builds next-generation AI computers, combining expertise in computer architecture, ASIC design, systems, and neural network compilers Offices worldwide Join our team! | Computer Hardware Manufacturing | 🇨🇦 Toronto | 1,226 | 2016 |
| 82 | [Armstrong Fluid Technology](https://www.tamtam.ai/c/armstrong-fluid-technology) (armstrongfluidtechnology.com)<br>A global leader in intelligent fluid flow equipment and optimization technologies, focusing on HVAC, plumbing, gas transmission, and fire safety applications | Industrial Machinery Manufacturing | 🇨🇦 Toronto | 1,224 | 1934 |
| 83 | [Women's College Hospital](https://www.tamtam.ai/c/women-s-college-hospital) (womenscollegehospital.ca)<br>A pioneering healthcare institution focusing on women's health, innovation, and addressing Canada's healthcare challenges through interdisciplinary teams and equitable work environment | Hospitals and Health Care | 🇨🇦 Toronto | 1,200 |  |
| 84 | [Candu Energy Inc.](https://www.tamtam.ai/c/candu-energy-inc) (snclavalin.com)<br>A leading developer of CANDU® reactors, providing clean and reliable electricity solutions internationally while meeting top safety and regulatory standards | Civil Engineering | 🇨🇦 Mississauga | 1,187 |  |
| 85 | [Valiant TMS](https://www.tamtam.ai/c/valiant-tms) (valianttms.com)<br>An Industry 40 system integrator specializing in digitalization, process development, design, and technology integration with global strategic teams | Automation Machinery Manufacturing | 🇨🇦 Windsor | 1,105 | 1959 |
| 86 | [University of Ottawa Heart Institute](https://www.tamtam.ai/c/university-of-ottawa-heart-institute) (ottawaheart.ca)<br>A leading cardiovascular health center in Canada providing high-tech, personalized care, advancing cardiac medicine through research, and pioneering new treatments globally | Hospitals and Health Care | 🇨🇦 Ottawa | 1,087 |  |
| 87 | [Holland Bloorview Kids Rehabilitation Hospital](https://www.tamtam.ai/c/holland-bloorview-kids-rehabilitation-hospital) (hollandbloorview.ca)<br>Pioneering treatments, technologies, and programs for children with disabilities to fully participate in life through a world-class teaching hospital | Hospitals and Health Care | 🇨🇦 Toronto | 1,086 |  |
| 88 | [Cohere](https://www.tamtam.ai/c/cohere) (cohere.com)<br>Building cutting-edge foundation models and end-to-end AI products for businesses, with a focus on data security and privacy across various deployment options. | Software Development | 🇨🇦 Toronto | 1,020 | 2019 |
| 89 | [Docebo](https://www.tamtam.ai/c/docebo) (docebo.com)<br>Provides a comprehensive learning platform that enables organizations to deliver personalized training and measure the effectiveness of their learning initiatives. | Software Development | 🇨🇦 Toronto | 1,016 | 2005 |
| 90 | [Brock Solutions](https://www.tamtam.ai/c/brock-solutions) (brocksolutions.com)<br>Global industrial automation and professional services provider specializing in Manufacturing, Transportation, and Utilities with expertise in engineering software and solutions | Automation Machinery Manufacturing | 🇨🇦 Kitchener | 976 | 1992 |
| 91 | [Sherritt International Corporation](https://www.tamtam.ai/c/sherritt-international-corporation) (sherritt.com)<br>A global leader in mining nickel and cobalt, creating innovative environmental solutions for oil and mining industries, and a major energy producer | Mining | 🇨🇦 Toronto | 934 |  |
| 92 | [Canadian Bank Note Company, Limited](https://www.tamtam.ai/c/canadian-bank-note-company-limited) (cbnco.com)<br>The company specializes in providing secure identification solutions, including currency, passports, driver licenses, and biometric solutions, to prevent fraud globally | IT Services and IT Consulting | 🇨🇦 Ottawa | 925 | 1897 |
| 93 | [The Woodbridge Group](https://www.tamtam.ai/c/the-woodbridge-group) (woodbridgegroup.com)<br>Innovative urethane and bead foam technologies for automotive and other industries worldwide, providing comfort, safety, acoustics, insulation, and structural solutions Offering diverse services | Motor Vehicle Manufacturing | 🇨🇦 Mississauga | 915 |  |
| 94 | [Temerty Faculty of Medicine, University of Toronto](https://www.tamtam.ai/c/temerty-faculty-of-medicine-university-of-toronto) (temertymedicine.utoronto.ca)<br>Leader in medical research and innovation, collaborating with diverse partners to address global health challenges for over a century | Higher Education | 🇨🇦 Toronto | 913 |  |
| 95 | [Princess Margaret Cancer Centre](https://www.tamtam.ai/c/princess-margaret-cancer-centre) (uhn.ca)<br>Keep up-to-date on the latest developments and changes at a prominent hospital through news articles and general information | Medical Practices | 🇨🇦 Toronto | 898 |  |
| 96 | [Providence Care](https://www.tamtam.ai/c/providence-care) (providencecare.ca)<br>Leading provider of specialized care in aging, mental health, and rehabilitation, offering hospital, long-term care, hospice, and community-based services with a focus on independence and quality of life | Hospitals and Health Care | 🇨🇦 Kingston | 898 | 1861 |
| 97 | [Zafin](https://www.tamtam.ai/c/zafin) (zafin.com)<br>Zafin offers a SaaS product and pricing platform for top banks worldwide, simplifying core modernization, accelerating time to market, and enabling personalized pricing | Software Development | 🇨🇦 Toronto | 870 |  |
| 98 | [Cority](https://www.tamtam.ai/c/cority) (cority.com)<br>Empowering employees with EHS software solutions to reduce risks, improve efficiencies, and create a safer, healthier, and more sustainable world | Software Development | 🇨🇦 Toronto | 864 |  |
| 99 | [Teledyne DALSA](https://www.tamtam.ai/c/teledyne-dalsa) (teledynedalsa.com)<br>Specialized in high-performance image sensing, semiconductor fabrication, and 3D geospatial systems with global R&D and support locations. | Appliances, Electrical, and Electronics Manufacturing | 🇨🇦 Waterloo | 863 | 1980 |
| 100 | [Ground Effects Ltd.](https://www.tamtam.ai/c/ground-effects-ltd) (gfxltd.com)<br>A manufacturer of OEM-level automotive accessories that started in Canada and now has nearly 40 locations worldwide | Motor Vehicle Manufacturing | 🇨🇦 Tecumseh | 862 | 1986 |

## 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 12, 2026.

## More company lists in Ontario

- [The largest companies in Ontario](https://www.tamtam.ai/l/largest-companies-ontario) (5,032)
- [Multinational companies in Ontario](https://www.tamtam.ai/l/multinational-companies-ontario) (901)
- [Financial services firms in Ontario](https://www.tamtam.ai/l/financial-services-firms-ontario) (396)
- [Manufacturers in Ontario](https://www.tamtam.ai/l/manufacturers-ontario) (389)
- [Critical infrastructure operators in Ontario](https://www.tamtam.ai/l/critical-infrastructure-operators-ontario) (344)
- [Retail chains in Ontario](https://www.tamtam.ai/l/retail-chains-ontario) (327)
- [Logistics companies in Ontario](https://www.tamtam.ai/l/logistics-companies-ontario) (285)
- [Education providers in Ontario](https://www.tamtam.ai/l/education-companies-ontario) (276)
- [SaaS companies in Ontario](https://www.tamtam.ai/l/saas-companies-ontario) (275)
- [Truck Transportation companies in Ontario](https://www.tamtam.ai/l/truck-transportation-companies-ontario) (270)
- [Transportation, Logistics, Supply Chain and Storage companies in Ontario](https://www.tamtam.ai/l/transportation-logistics-supply-chain-and-storage-companies-ontario) (261)
- [Public sector organisations in Ontario](https://www.tamtam.ai/l/public-sector-organisations-ontario) (259)
- [Financial Services companies in Ontario](https://www.tamtam.ai/l/financial-services-companies-ontario) (250)
- [IT Services and IT Consulting companies in Ontario](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-ontario) (235)
- [Software Development companies in Ontario](https://www.tamtam.ai/l/software-development-companies-ontario) (231)
- [Healthcare providers in Ontario](https://www.tamtam.ai/l/healthcare-providers-ontario) (226)
- [Hardware manufacturers in Ontario](https://www.tamtam.ai/l/hardware-companies-ontario) (213)
- [Professional services firms in Ontario](https://www.tamtam.ai/l/professional-services-firms-ontario) (211)
- [Hospitals and Health Care companies in Ontario](https://www.tamtam.ai/l/hospitals-and-health-care-companies-ontario) (205)
- [Distributors and wholesalers in Ontario](https://www.tamtam.ai/l/distributors-and-wholesalers-ontario) (183)
- [Companies with a mobile app in Ontario](https://www.tamtam.ai/l/companies-with-mobile-app-ontario) (181)
- [Publicly traded companies in Ontario](https://www.tamtam.ai/l/publicly-traded-companies-ontario) (156)
- [IT services companies in Ontario](https://www.tamtam.ai/l/it-services-companies-ontario) (156)
- [Subscription businesses in Ontario](https://www.tamtam.ai/l/subscription-businesses-ontario) (153)

## The same list elsewhere in Canada

- [Companies with in-house R&D in Canada](https://www.tamtam.ai/l/r-and-d-companies-canada) (678)
- [Companies with in-house R&D in the province of Quebec](https://www.tamtam.ai/l/r-and-d-companies-province-of-quebec) (159)
- [Companies with in-house R&D in British Columbia](https://www.tamtam.ai/l/r-and-d-companies-british-columbia) (76)
- [Companies with in-house R&D in Alberta](https://www.tamtam.ai/l/r-and-d-companies-alberta) (74)
- [Companies with in-house R&D in Toronto](https://www.tamtam.ai/l/r-and-d-companies-toronto) (93)
- [Companies with in-house R&D in Montreal](https://www.tamtam.ai/l/r-and-d-companies-montreal) (59)
- [Companies with in-house R&D in Calgary](https://www.tamtam.ai/l/r-and-d-companies-calgary) (39)
- [Companies with in-house R&D in Vancouver](https://www.tamtam.ai/l/r-and-d-companies-vancouver) (34)

## The same list elsewhere

- [Companies with in-house R&D in the world](https://www.tamtam.ai/l/r-and-d-companies-in-the-world) (34,346)
- [Companies with in-house R&D in North America](https://www.tamtam.ai/l/r-and-d-companies-in-north-america) (7,619)

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Source: https://www.tamtam.ai/l/r-and-d-companies-ontario