These Ottawa-based organizations are primarily large educational institutions, including universities, colleges, and school boards, alongside several significant non-profit and public service entities. The University of Ottawa, the largest bilingual university globally, and Carleton University, known for its research and teaching, are prominent. Other key organizations include the Ottawa-Carleton District School Board, providing diverse educational programs, and Algonquin College, which focuses on hands-on learning.
A clear pattern among these organizations is their strong focus on education and public service within the Ottawa region. While higher education institutions like Collège La Cité and the University of Ottawa Heart Institute are well-represented, the presence of entities such as the Canadian Red Cross and the Canada School of Public Service highlights a broader commitment to community welfare and governmental training.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
University of Ottawauottawa.ca
The company is the largest bilingual university in the world, offering education in English and French with a focus on research and global advancements |
12,220 | |||
| 2 |
Carleton Universitycarleton.ca
University located near government and high tech companies, combining research and teaching to provide superior education and solve real problems. |
6,886 | |||
| 3 |
Ottawa-Carleton District School Board (OCDSB)ocdsb.ca
A large school board in Eastern Ontario offering a wide range of programs to support students in academics, arts, athletics, and technology |
6,863 | |||
| 4 |
Algonquin College of Applied Arts and Technologyalgonquincollege.com
Leading college in eastern Ontario offering diverse hands-on learning programs, including degrees, diplomas, and certificates, with a strong focus on student success and innovation |
4,972 | |||
| 5 |
Ottawa Catholic School Boardocsb.ca
Providing faith-based, inclusive education with English and French programs, fostering critical thinking, creativity, well-being, and community connections. |
4,559 | |||
| 6 |
Canadian Red Crossredcross.ca
An organization within the International Red Cross and Red Crescent Movement providing disaster relief, emergency response, prevention training, capacity building, and community health services |
4,268 | |||
| 7 |
Collège La Citécollegelacite.ca
Discover life in the largest French-speaking college in Ontario Stay informed about job opportunities Dynamic, inclusive environment with top employer rankings Follow on social media for more |
2,069 | |||
| 8 |
Conseil des écoles publiques de l'Est de l'Ontario (CEPEO)cepeo.on.ca
A leading public school board in Eastern Ontario offering diverse and inclusive educational opportunities for students and employees to thrive |
1,604 | |||
| 9 |
Calian Groupcalian.com
Employees engineer reliable solutions solving complex problems for healthcare, communications, learning, and security sectors. Diverse products, services and solutions globally. |
1,396 | |||
| 10 |
University of Ottawa Heart Instituteottawaheart.ca
A leading cardiovascular health center in Canada providing high-tech, personalized care, advancing cardiac medicine through research, and pioneering new treatments globally |
1,087 | |||
| 11 |
Canada School of Public Service | École de la fonction publique du Canadacsps-efpc.gc.ca
The Canada School of Public Service provides tailored learning products for the Canadian Public Service, helping employees apply relevant knowledge in their work environments |
866 | |||
| 12 |
Digital Opportunity Trustdotrust.org
Support youth innovators to develop and apply digital solutions, collaborating with sectors to drive inclusive community transformation globally. |
695 | |||
| 13 |
Royal College of Physicians and Surgeons of Canadaroyalcollege.ca
Specialist medical education organization partnering with healthcare collaborators to set standards, promote research, advocacy, and continuous improvement for specialist physicians |
678 | |||
| 14 |
World University Service of Canada (WUSC - EUMC)wusc.ca
A Canadian non-profit organization empowering youth worldwide through education, economic opportunities, and resettlement support for student refugees |
653 | |||
| 15 |
Collège La Citécollegelacite.ca
The company is the largest French-language applied arts and technology college in Ontario, offering over 90 programs to 4700 students |
538 | |||
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 |
National Arts Centre | Centre national des Artsnac-cna.ca
A national arts organization in Canada collaborates with artists and organizations to create a stage for performing arts, youth education, and new media initiatives |
498 | |||
| 17 |
Canadian Medical Protective Associationcmpa-acpm.ca
A leading provider of medical liability protection and professional development for Canadian physicians, offering risk management education and legal advice |
481 | |||
| 18 |
Croix-Rouge canadiennecroixrouge.ca
The company helps people and communities in need in Canada and around the world, strengthening their resilience through fundamental principles |
425 | |||
| 19 |
Telfer School of Management at the University of Ottawatelfer.uottawa.ca
An educational institution dedicated to shaping purpose-driven leaders and responsible managers for a greener, healthier, wealthier, and more prosperous future globally |
413 | |||
| 20 |
St. John Ambulance Canada | Ambulance Saint-Jeansja.ca
Leading provider of first aid and CPR training, offering customizable courses, account management, and preferential pricing on life-saving programs and safety products |
399 | |||
| 21 |
Saint Paul Universityustpaul.ca
A bilingual university in Ottawa offering undergraduate and graduate programs in various disciplines with a focus on the human experience |
383 | |||
| 22 |
Ingeniumingeniumcanada.org
Ingenium creates a collaborative space celebrating creativity and human ingenuity by telling stories of innovation through three museums focusing on science and technology |
354 | |||
| 23 |
Bureau de l'éducation internationale du CECCEinternational.ecolecatholique.ca
A leading French-language school network outside Quebec, offering high academic achievement, bilingual education from grade 4, and diverse post-secondary opportunities |
347 | |||
| 24 |
Acadiumacadium.com
This organization provides free and accessible education to individuals worldwide, having trained 90,000 students and partnered with 40,000 businesses |
328 | |||
| 25 |
Perley Healthperleyhealth.ca
Senior and Veteran community providing long-term care, independent living, clinical services, research, education, and innovative care for Canada's aging population |
322 | |||
| 26 |
Andrew Fleck Children's Servicesafchildrensservices.ca
A leading charitable organization in Ottawa providing high-quality early learning and family support services for children and families since 1911 |
186 | |||
| 27 |
Sprott School of Business at Carleton Universitysprott.carleton.ca
Challenging business to make a positive impact, creating learning experiences and scholarship to improve lives worldwide, located in Ottawa |
183 | |||
| 28 | 134 | ||||
| 29 |
LemonadeLXPlemonadelxp.com
A company offering an award-winning learning experience and digital adoption platform to transform corporate training, upskill employees, and facilitate tech adoption |
34 | |||
| 30 |
aggregate intellectai.science
Offering fractional generative AI labs for seamless integration of AI into sales workflows, empowering industries with on-demand AI expertise |
14 | |||
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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 Ottawa
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- Public sector organisations in Ottawa 49
- Multinational companies in Ottawa 42
- Critical infrastructure operators in Ottawa 30
- Government Administration companies in Ottawa 30